Question

isosceles triangles
the vertex angle of an isosceles triangle measures 40°. what is the measure of a base angle?
140°
100°
40°
70°

Explanation:

the measure of each base angle be \(x\). The vertex angle is \(40^{\circ}\). So, \(x + x+40^{\circ}=180^{\circ}\), which simplifies to \(2x=180^{\circ}- 40^{\circ}=140^{\circ}\).

Step3: Solve for \(x\)

Divide both sides of \(2x = 140^{\circ}\) by 2. \(x=\frac{140^{\circ}}{2}=70^{\circ}\).

Answer:

\(70^{\circ}\)