In a right triangle, if angle $A$ measures $30°$, what is the measure of angle $B$?

• A. $45°$
• B. $90°$
• C. $30°$
• D. $60°$

Answer: (D)

Verified step by step guidance

1. Recall that the sum of the interior angles in any triangle is always \(180^\circ\).
2. Since the triangle is a right triangle, one of its angles is \(90^\circ\) by definition.
3. Given that angle \(A\) measures \(30^\circ\), write the equation for the sum of angles: \(A + B + 90^\circ = 180^\circ\).
4. Substitute the known value of angle \(A\) into the equation: \(30^\circ + B + 90^\circ = 180^\circ\).
5. Solve for angle \(B\) by isolating it: \(B = 180^\circ - 90^\circ - 30^\circ\).