If two angles are supplementary and one angle measures $65°$, what is the measure of its supplementary angle?

• A. $25°$
• B. $35°$
• C. $90°$
• D. $115°$

Answer: (D)

Verified step by step guidance

1. Recall that supplementary angles are two angles whose measures add up to 180 degrees. This means if one angle is \( A \), the other angle \( B \) satisfies \( A + B = 180^\circ \).
2. Identify the given angle measure. Here, one angle is given as \( 65^\circ \).
3. Set up the equation for the supplementary angle: \( 65^\circ + B = 180^\circ \).
4. Solve for \( B \) by subtracting \( 65^\circ \) from both sides: \( B = 180^\circ - 65^\circ \).
5. Simplify the expression to find the measure of the supplementary angle.