What is (72^\circ 30') in decimal degrees?

Correct answer: (72.5^\circ)

The direct answer is option B, \(72.5^\circ\). In degree-minute notation, one degree contains 60 minutes, so 30 minutes is half a degree: \(30'=\frac{30}{60}^\circ=0.5^\circ\). Add this to the whole-degree part: \(72^\circ+0.5^\circ=72.5^\circ\). Option B is correct. Option A, \(72.3^\circ\), wrongly treats 30 minutes as 0.3 degree. Option C, \(73.0^\circ\), treats 30 minutes as a full degree. Option D, \(72.25^\circ\), would represent 15 minutes, because \(15/60=0.25\), not 30 minutes. The key rule is that minutes are a fraction of a degree, not decimal digits written after the degree number. Memory cue: divide arc-minutes by 60 before adding.