Question

the diagram shows a triangle. what is the value of a? a = °

Explanation:

Step1: Recall angle - sum property

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

Step2: Set up the equation

Let the three angles of the triangle be 43°, 99°, and \(a\). Then \(43 + 99+a=180\).

Step3: Simplify the left - hand side

\(142 + a=180\).

Step4: Solve for \(a\)

Subtract 142 from both sides: \(a=180 - 142\).
\(a = 38\).

Answer:

38