Question

note: figure not drawn to scale.
in the right triangle shown, what is the value of ( a )?
a 13
b 77
c 90
d 103

Explanation:

Step1: Recall the sum of angles in a triangle

The sum of the interior angles of a triangle is \(180^{\circ}\). In a right - triangle, one angle is \(90^{\circ}\).

Step2: Set up the equation

Let the given non - right angle be \(13^{\circ}\) and the unknown angle be \(a^{\circ}\). Then \(90 + 13+a=180\).

Step3: Solve the equation for \(a\)

First, simplify the left - hand side of the equation: \(103 + a=180\). Then subtract \(103\) from both sides: \(a = 180-103\). So \(a = 77\).

Answer:

B. 77