Question

what is the value of s?

Explanation:

Step1: Use the exterior - angle theorem

The exterior - angle theorem states that the measure of an exterior angle of a triangle is equal to the sum of the measures of the two non - adjacent interior angles.
So, \(s+(s - 43^{\circ})=s + 43^{\circ}\)

Step2: Simplify the equation

Expand the left - hand side: \(s+s-43^{\circ}=s + 43^{\circ}\)
\(2s-43^{\circ}=s + 43^{\circ}\)
Subtract \(s\) from both sides: \(2s-s-43^{\circ}=s - s+43^{\circ}\)
\(s-43^{\circ}=43^{\circ}\)
Add \(43^{\circ}\) to both sides: \(s-43^{\circ}+43^{\circ}=43^{\circ}+43^{\circ}\)

Answer:

\(s = 86^{\circ}\)