Question

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

Explanation:

Step1: Recall angle - sum property of a triangle

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

Step2: Set up an equation

Let the three angles of the triangle be 39°, 111°, and \(a\). So, \(39 + 111+a=180\).

Step3: Simplify the left - hand side

\(39 + 111=150\), so the equation becomes \(150 + a=180\).

Step4: Solve for \(a\)

Subtract 150 from both sides: \(a=180 - 150\).
\(a = 30\)

Answer:

30