All ISEE Upper Level Math Resources
Example Question #5 : Solve Simple Equations For An Unknown Angle In A Figure: Ccss.Math.Content.7.G.B.5
One of the base angles of an isosceles triangle is . Give the measure of the vertex angle.
The base angles of an isosceles triangle are always equal. Therefore both base angles are .
Let the measure of the third angle. Since the sum of the angles of a triangle is , we can solve accordingly: