Question

15 the values of two angles of a triangle are 30° and 60°, respectively. calculate the value of the third angle of the triangle in degrees. a 60° b 70° c 80° d 90°

Explanation:

Step1: Recall angle - sum property

The sum of the interior angles of a triangle is 180°. Let the three angles be \(A\), \(B\), and \(C\). So \(A + B+C=180^{\circ}\).

Step2: Substitute known angles

We know \(A = 30^{\circ}\) and \(B = 60^{\circ}\). Then \(C=180^{\circ}-A - B\).

Step3: Calculate the third - angle

\(C=180^{\circ}-30^{\circ}-60^{\circ}=90^{\circ}\)

Answer:

D. \(90^{\circ}\)