Question

find the measure of the missing angle.

Explanation:

Step1: Recall angle - sum property

The right - angle shown is 90°. Let the missing angle be \(a\). The sum of the two non - overlapping angles forming the right - angle is 90°.

Step2: Set up the equation

If one of the angles is 69°, then \(a+69^{\circ}=90^{\circ}\).

Step3: Solve for \(a\)

Subtract 69° from both sides of the equation: \(a = 90^{\circ}-69^{\circ}\).
\(a = 21^{\circ}\)

Answer:

\(21^{\circ}\)