To find the measure of angle A in the right triangle, we can use the definition of the tangent function, which is the ratio of the opposite side to the adjacent side. In this case:
- The side opposite angle A is side B (12).
- The side adjacent to angle A is side A (5).
We can find the tangent of angle A using the formula:
\[ \tan(A) = \frac{\text{opposite}}{\text{adjacent}} = \frac{B}{A} = \frac{12}{5} \]
Next, we use the inverse tangent function to find angle A:
\[ A = \tan^{-1}\left(\frac{12}{5}\right) \]
Calculating \( \frac{12}{5} \) gives us 2.4. Now we can find \( \tan^{-1}(2.4) \) using a calculator:
\[ A \approx 67.38^\circ \]
Rounding to the nearest whole degree, angle A is approximately 67°.
So the correct answer is:
67°.