Question

Find the unknown angle for the following right triangle: Angle A Angle B Angle C A:? B:90 degrees C:27 degrees

Answer 1

The sum of the interior angles of a triangle is 180°.

Then, to solve this question, follow the steps below.

Step 01: Write an equation that represents the sum of the interior angles.

Given the angles ∠A, ∠B, and ∠C, then:

`\angle A+\angle B+\angle C=180\degree`

Step 02: Substitute the known angles in the equation.

∠B = 90°

∠C = 27°

`\begin{gathered} \angle A+90+27=180\degree \\ \angle A+117=180 \end{gathered}`

Step 03: Isolate ∠A.

To do it, subtract 117 from both sides.

`\begin{gathered} \angle A+117-117=180-117 \\ \angle A=63\degree \end{gathered}`

Answer: ∠A = 63°.