Question

What is the measure of a third angle in a triangle if the first angle is equal to 89° and the second angle is equal to 46°? *A.45°B.54°C.65°D.73°E.Cannot be determined from the information above

Answer 1

According to the triangle sum theorem, the sum of the angles in a triangle is 180°. Using the measures of the given angles, you can find the third angle by using this theorem:

$\begin{gathered} 89+46+\measuredangle3=180 \\ 135+\measuredangle3=180 \\ \measuredangle3=180-135 \\ \measuredangle3=45 \end{gathered}$

It means that the correct answer is A. 45°.