\(\theta=\frac{11}{21}\) radians and the degree measure is \(\frac{11}{21}\times\frac{180^\circ\times7}{22}=30^\circ\). In exams, convert radians to degrees carefully.
Step 2
Why this answer is correct
The correct answer is B. \(30^\circ\). \(\theta=\frac{11}{21}\) radians and the degree measure is \(\frac{11}{21}\times\frac{180^\circ\times7}{22}=30^\circ\). In exams, convert radians to degrees carefully.
Step 3
Exam Tip
\(\theta=\frac{11}{21}\) रेडियन और डिग्री माप \(\frac{11}{21}\times\frac{180^\circ\times7}{22}=30^\circ\) है। परीक्षा में रेडियन से डिग्री में सावधानी से बदलें।
The area ratio is \(\frac{\theta}{2\pi}\). From \(\frac{\theta}{2\pi}=\frac{3}{4}\) we get \(\theta=\frac{3\pi}{2}\).
Step 2
Why this answer is correct
The correct answer is C. \(\frac{3\pi}{2}\). The area ratio is \(\frac{\theta}{2\pi}\). From \(\frac{\theta}{2\pi}=\frac{3}{4}\) we get \(\theta=\frac{3\pi}{2}\).
Step 3
Exam Tip
क्षेत्रफल का अनुपात \(\frac{\theta}{2\pi}\) होता है। \(\frac{\theta}{2\pi}=\frac{3}{4}\) से \(\theta=\frac{3\pi}{2}\) है।
One third of the circumference gives one third of the full angle \(2\pi\). Hence the central angle is \(\frac{2\pi}{3}\).
Step 2
Why this answer is correct
The correct answer is B. \(\frac{2\pi}{3}\). One third of the circumference gives one third of the full angle \(2\pi\). Hence the central angle is \(\frac{2\pi}{3}\).
Step 3
Exam Tip
परिधि का \(\frac{1}{3}\) भाग पूरे कोण \(2\pi\) का \(\frac{1}{3}\) भाग देगा। इसलिए केंद्रीय कोण \(\frac{2\pi}{3}\) है।
For fixed arc length \(\theta\) is inversely proportional to radius. The new radius is \(\frac{5}{4}\) times so the new angle is \(\frac{\pi}{2}\).
Step 2
Why this answer is correct
The correct answer is C. \(\frac{\pi}{2}\). For fixed arc length \(\theta\) is inversely proportional to radius. The new radius is \(\frac{5}{4}\) times so the new angle is \(\frac{\pi}{2}\).
Step 3
Exam Tip
चाप लंबाई स्थिर हो तो \(\theta\) त्रिज्या के व्युत्क्रमानुपाती है। नई त्रिज्या \(\frac{5}{4}\) गुना है इसलिए नया कोण \(\frac{\pi}{2}\) होगा।
\(36+18\theta=48\), so \(\theta=\frac{2}{3}\) radians. In degrees, this is \(\frac{2}{3}\times\frac{180}{\pi}=\frac{120}{\pi}^\circ\).
Step 2
Why this answer is correct
The correct answer is C. \(\frac{120}{\pi}^\circ\). \(36+18\theta=48\), so \(\theta=\frac{2}{3}\) radians. In degrees, this is \(\frac{2}{3}\times\frac{180}{\pi}=\frac{120}{\pi}^\circ\).
Step 3
Exam Tip
\(36+18\theta=48\), इसलिए \(\theta=\frac{2}{3}\) रेडियन है। डिग्री में यह \(\frac{2}{3}\times\frac{180}{\pi}=\frac{120}{\pi}^\circ\) है।
From \(A=\frac{1}{2}rs\), (r=8), then \(\theta=\frac{s}{r}=\frac{25}{8}\). In exams, find the radius first from arc length and area.
Step 2
Why this answer is correct
The correct answer is B. \(\frac{25}{8}\). From \(A=\frac{1}{2}rs\), (r=8), then \(\theta=\frac{s}{r}=\frac{25}{8}\). In exams, find the radius first from arc length and area.
Step 3
Exam Tip
\(A=\frac{1}{2}rs\) से (r=8), फिर \(\theta=\frac{s}{r}=\frac{25}{8}\)। परीक्षा में चाप और क्षेत्रफल से पहले त्रिज्या निकालें।
\(144^\circ=\frac{4\pi}{5}\) and \(A=\frac{1}{2}\times225\times\frac{4\pi}{5}=90\pi\). In exams, converting degrees into radians is essential.
Step 2
Why this answer is correct
The correct answer is C. \(90\pi\) वर्ग सेमी / \(90\pi\) square cm. \(144^\circ=\frac{4\pi}{5}\) and \(A=\frac{1}{2}\times225\times\frac{4\pi}{5}=90\pi\). In exams, converting degrees into radians is essential.
Step 3
Exam Tip
\(144^\circ=\frac{4\pi}{5}\) और \(A=\frac{1}{2}\times225\times\frac{4\pi}{5}=90\pi\)। परीक्षा में डिग्री को रेडियन में बदलना जरूरी है।
From \(s=r\theta\), (r=4), then \(A=\frac{1}{2}r^2\theta=32\). In exams, first find the radius and then apply the area formula.
Step 2
Why this answer is correct
The correct answer is A. (32) वर्ग सेमी / (32) square cm. From \(s=r\theta\), (r=4), then \(A=\frac{1}{2}r^2\theta=32\). In exams, first find the radius and then apply the area formula.
Step 3
Exam Tip
\(s=r\theta\) से (r=4), फिर \(A=\frac{1}{2}r^2\theta=32\)। परीक्षा में पहले त्रिज्या निकालकर क्षेत्रफल लगाएं।
\(75\pi=\frac{1}{2}\times100\times\theta\), so \(\theta=\frac{3\pi}{2}=270^\circ\). In exams, \(\theta\) is in radians in the area formula.
Step 2
Why this answer is correct
The correct answer is D. \(270^\circ\). \(75\pi=\frac{1}{2}\times100\times\theta\), so \(\theta=\frac{3\pi}{2}=270^\circ\). In exams, \(\theta\) is in radians in the area formula.
Step 3
Exam Tip
\(75\pi=\frac{1}{2}\times100\times\theta\), इसलिए \(\theta=\frac{3\pi}{2}=270^\circ\)। परीक्षा में क्षेत्रफल सूत्र में \(\theta\) रेडियन में होता है।
From \(s=r\theta\), \(\theta=\frac{3\pi}{8}\), which is \(67.5^\circ\). In exams, keep the angle in radians in the arc formula.
Step 2
Why this answer is correct
The correct answer is C. \(67.5^\circ\). From \(s=r\theta\), \(\theta=\frac{3\pi}{8}\), which is \(67.5^\circ\). In exams, keep the angle in radians in the arc formula.
Step 3
Exam Tip
\(s=r\theta\) से \(\theta=\frac{3\pi}{8}\), जो \(67.5^\circ\) है। परीक्षा में चाप सूत्र में कोण रेडियन में रखें।
Sector area is \(\frac{1}{2}r^2\theta\). So \(\frac{1}{2}\times36\times\frac{5\pi}{9}=10\pi\).
Step 2
Why this answer is correct
The correct answer is C. \(10\pi\) वर्ग सेमी / \(10\pi\) sq cm. Sector area is \(\frac{1}{2}r^2\theta\). So \(\frac{1}{2}\times36\times\frac{5\pi}{9}=10\pi\).
Step 3
Exam Tip
त्रिज्यखंड क्षेत्रफल \(\frac{1}{2}r^2\theta\) होता है। इसलिए \(\frac{1}{2}\times36\times\frac{5\pi}{9}=10\pi\) है।
B. \(\frac{14\pi}{3}\) सेमी/\(\frac{14\pi}{3}\) cm
Step 1
Concept
\(40^\circ=\frac{2\pi}{9}\) and \(s=21\times\frac{2\pi}{9}=\frac{14\pi}{3}\). In exams, convert degrees into radians and apply \(s=r\theta\).
Step 2
Why this answer is correct
The correct answer is B. \(\frac{14\pi}{3}\) सेमी / \(\frac{14\pi}{3}\) cm. \(40^\circ=\frac{2\pi}{9}\) and \(s=21\times\frac{2\pi}{9}=\frac{14\pi}{3}\). In exams, convert degrees into radians and apply \(s=r\theta\).
Step 3
Exam Tip
\(40^\circ=\frac{2\pi}{9}\) और \(s=21\times\frac{2\pi}{9}=\frac{14\pi}{3}\)। परीक्षा में डिग्री को रेडियन में बदलकर \(s=r\theta\) लगाएं।
\(s=r\theta\), so \(r=\frac{10\pi}{\frac{2\pi}{3}}=15\). In exams, multiply by the reciprocal while dividing by a fraction.
Step 2
Why this answer is correct
The correct answer is C. (15) सेमी / (15) cm. \(s=r\theta\), so \(r=\frac{10\pi}{\frac{2\pi}{3}}=15\). In exams, multiply by the reciprocal while dividing by a fraction.
Step 3
Exam Tip
\(s=r\theta\), इसलिए \(r=\frac{10\pi}{\frac{2\pi}{3}}=15\)। परीक्षा में भिन्न से भाग देते समय उल्टा गुणा करें।
Sector area is \(A=\frac{1}{2}r^2\theta\), so \(24=18\theta\). In exams, use \(\theta\) in radians in the area formula.
Step 2
Why this answer is correct
The correct answer is B. \(\frac{4}{3}\). Sector area is \(A=\frac{1}{2}r^2\theta\), so \(24=18\theta\). In exams, use \(\theta\) in radians in the area formula.
Step 3
Exam Tip
सेक्टर क्षेत्रफल \(A=\frac{1}{2}r^2\theta\), इसलिए \(24=18\theta\)। परीक्षा में क्षेत्रफल सूत्र में \(\theta\) रेडियन में ही लें।
\(s=r\theta=5\times\frac{7\pi}{10}=\frac{7\pi}{2}\) cm. In exams, put the radian angle directly in the formula.
Step 2
Why this answer is correct
The correct answer is B. \(\frac{7\pi}{2}\) सेमी / \(\frac{7\pi}{2}\) cm. \(s=r\theta=5\times\frac{7\pi}{10}=\frac{7\pi}{2}\) cm. In exams, put the radian angle directly in the formula.
Step 3
Exam Tip
\(s=r\theta=5\times\frac{7\pi}{10}=\frac{7\pi}{2}\) सेमी। परीक्षा में रेडियन कोण को सीधे सूत्र में रखें।
\(144^\circ=\frac{4\pi}{5}\) and \(40\pi=\frac{1}{2}r^2\cdot\frac{4\pi}{5}\) gives (r=10). Keep the angle in radians in the area formula.
Step 2
Why this answer is correct
The correct answer is C. (10) सेमी / (10) cm. \(144^\circ=\frac{4\pi}{5}\) and \(40\pi=\frac{1}{2}r^2\cdot\frac{4\pi}{5}\) gives (r=10). Keep the angle in radians in the area formula.
Step 3
Exam Tip
\(144^\circ=\frac{4\pi}{5}\) और \(40\pi=\frac{1}{2}r^2\cdot\frac{4\pi}{5}\) से (r=10) है। क्षेत्रफल सूत्र में कोण रेडियन में रखें।
\(225^\circ=\frac{5\pi}{4}\) and \(r=\frac{s}{\theta}=\frac{25\pi}{5\pi/4}=20\). Convert the angle to radians first.
Step 2
Why this answer is correct
The correct answer is B. (20) सेमी / (20) cm. \(225^\circ=\frac{5\pi}{4}\) and \(r=\frac{s}{\theta}=\frac{25\pi}{5\pi/4}=20\). Convert the angle to radians first.
Step 3
Exam Tip
\(225^\circ=\frac{5\pi}{4}\) और \(r=\frac{s}{\theta}=\frac{25\pi}{5\pi/4}=20\) है। कोण को पहले रेडियन में बदलें।
Using \(A=\frac{1}{2}rs\), \(121=\frac{1}{2}r\cdot22\), so (r=11) and \( \theta=\frac{s}{r}=2 \). When arc and area are given, find (r) first.
Step 2
Why this answer is correct
The correct answer is B. (2) रेडियन / (2) radians. Using \(A=\frac{1}{2}rs\), \(121=\frac{1}{2}r\cdot22\), so (r=11) and \( \theta=\frac{s}{r}=2 \). When arc and area are given, find (r) first.
Step 3
Exam Tip
\(A=\frac{1}{2}rs\) से \(121=\frac{1}{2}r\cdot22\) इसलिए (r=11) और \( \theta=\frac{s}{r}=2 \) है। चाप और क्षेत्रफल साथ दिए हों तो पहले (r) निकालें।
From \( \frac{81\pi}{8}=\frac{1}{2}\times81\times\theta \), \( \theta=\frac{\pi}{4}=45^\circ \). The angle from the sector area formula is in radians.
Step 2
Why this answer is correct
The correct answer is B. \(45^\circ\). From \( \frac{81\pi}{8}=\frac{1}{2}\times81\times\theta \), \( \theta=\frac{\pi}{4}=45^\circ \). The angle from the sector area formula is in radians.
Step 3
Exam Tip
\( \frac{81\pi}{8}=\frac{1}{2}\times81\times\theta \) से \( \theta=\frac{\pi}{4}=45^\circ \) है। क्षेत्रफल सूत्र में कोण रेडियन में निकलता है।
\( \theta=\frac{s}{r}=\frac{15\pi}{18}=\frac{5\pi}{6}=150^\circ \). First find the radian angle and then convert to degrees.
Step 2
Why this answer is correct
The correct answer is C. \(150^\circ\). \( \theta=\frac{s}{r}=\frac{15\pi}{18}=\frac{5\pi}{6}=150^\circ \). First find the radian angle and then convert to degrees.
Step 3
Exam Tip
\( \theta=\frac{s}{r}=\frac{15\pi}{18}=\frac{5\pi}{6}=150^\circ \) है। पहले रेडियन कोण निकालकर डिग्री में बदलें।
From \(54=\frac{1}{2}\times36\times\theta\), \( \theta=3 \) radians. Isolate the unknown angle in the sector area formula.
Step 2
Why this answer is correct
The correct answer is B. (3) रेडियन / (3) radians. From \(54=\frac{1}{2}\times36\times\theta\), \( \theta=3 \) radians. Isolate the unknown angle in the sector area formula.
Step 3
Exam Tip
\(54=\frac{1}{2}\times36\times\theta\) से \( \theta=3 \) रेडियन है। क्षेत्रफल सूत्र में अज्ञात कोण को अलग करें।
Area is \( \frac{1}{2}r^2\theta=\frac{1}{2}\times196\times\frac{5\pi}{7}=70\pi \). Use this formula directly with a radian angle.
Step 2
Why this answer is correct
The correct answer is C. \(70\pi\) वर्ग सेमी / \(70\pi\) square cm. Area is \( \frac{1}{2}r^2\theta=\frac{1}{2}\times196\times\frac{5\pi}{7}=70\pi \). Use this formula directly with a radian angle.
Step 3
Exam Tip
क्षेत्रफल \( \frac{1}{2}r^2\theta=\frac{1}{2}\times196\times\frac{5\pi}{7}=70\pi \) है। रेडियन कोण के साथ यह सूत्र सीधे लगाएं।
B. \( \frac{2\pi}{3} \) रेडियन/\( \frac{2\pi}{3} \) radians
Step 1
Concept
\( \theta=\frac{s}{r}=\frac{14\pi}{21}=\frac{2\pi}{3} \). Use \( \theta=\frac{s}{r} \) to find the angle from arc length.
Step 2
Why this answer is correct
The correct answer is B. \( \frac{2\pi}{3} \) रेडियन / \( \frac{2\pi}{3} \) radians. \( \theta=\frac{s}{r}=\frac{14\pi}{21}=\frac{2\pi}{3} \). Use \( \theta=\frac{s}{r} \) to find the angle from arc length.
Step 3
Exam Tip
\( \theta=\frac{s}{r}=\frac{14\pi}{21}=\frac{2\pi}{3} \) है। चाप लंबाई से कोण निकालते समय \( \theta=\frac{s}{r} \) लगाएं।
\( \theta=\frac{s}{r}=\frac{6\pi}{18}=\frac{\pi}{3}=60^\circ \). First find the radian angle and then convert it into degrees.
Step 2
Why this answer is correct
The correct answer is B. \(60^\circ\). \( \theta=\frac{s}{r}=\frac{6\pi}{18}=\frac{\pi}{3}=60^\circ \). First find the radian angle and then convert it into degrees.
Step 3
Exam Tip
\( \theta=\frac{s}{r}=\frac{6\pi}{18}=\frac{\pi}{3}=60^\circ \) है। पहले रेडियन कोण निकालकर डिग्री में बदलें।
\(25=\frac{1}{2}\times25\times\theta\), so \( \theta=2 \) radians. Isolate the unknown angle in the area formula.
Step 2
Why this answer is correct
The correct answer is B. (2) रेडियन / (2) radians. \(25=\frac{1}{2}\times25\times\theta\), so \( \theta=2 \) radians. Isolate the unknown angle in the area formula.
Step 3
Exam Tip
\(25=\frac{1}{2}\times25\times\theta\) इसलिए \( \theta=2 \) रेडियन है। क्षेत्रफल सूत्र में अज्ञात कोण को अलग करें।
Area is \( \frac{1}{2}r^2\theta=\frac{1}{2}\times100\times\frac{3\pi}{10}=15\pi \). Use this formula directly when the angle is in radians.
Step 2
Why this answer is correct
The correct answer is A. \(15\pi\) वर्ग सेमी / \(15\pi\) square cm. Area is \( \frac{1}{2}r^2\theta=\frac{1}{2}\times100\times\frac{3\pi}{10}=15\pi \). Use this formula directly when the angle is in radians.
Step 3
Exam Tip
क्षेत्रफल \( \frac{1}{2}r^2\theta=\frac{1}{2}\times100\times\frac{3\pi}{10}=15\pi \) है। कोण रेडियन में हो तो यह सूत्र सीधे लगाएं।
A. \( \frac{2}{3} \) रेडियन/\( \frac{2}{3} \) radian
Step 1
Concept
\( \theta=\frac{s}{r}=\frac{6}{9}=\frac{2}{3} \) radian. Use \(s=r\theta\) in arc length questions.
Step 2
Why this answer is correct
The correct answer is A. \( \frac{2}{3} \) रेडियन / \( \frac{2}{3} \) radian. \( \theta=\frac{s}{r}=\frac{6}{9}=\frac{2}{3} \) radian. Use \(s=r\theta\) in arc length questions.
Step 3
Exam Tip
\( \theta=\frac{s}{r}=\frac{6}{9}=\frac{2}{3} \) रेडियन है। चाप लंबाई वाले प्रश्नों में \(s=r\theta\) प्रयोग करें।
The sector area is \( \frac{1}{2}r^2\theta \) so \( \frac{1}{2}\times36\times\frac{\pi}{3}=6\pi \). Apply the formula directly when the angle is in radians.
Step 2
Why this answer is correct
The correct answer is C. \(6\pi\) वर्ग सेमी / \(6\pi\) square cm. The sector area is \( \frac{1}{2}r^2\theta \) so \( \frac{1}{2}\times36\times\frac{\pi}{3}=6\pi \). Apply the formula directly when the angle is in radians.
Step 3
Exam Tip
त्रिज्यखंड क्षेत्रफल \( \frac{1}{2}r^2\theta \) से \( \frac{1}{2}\times36\times\frac{\pi}{3}=6\pi \) है। कोण रेडियन में हो तो सूत्र सीधे लगाएं।
