HELP!!
The Transamerica Pyramid building shown in the photograph has four faces shaped like isosceles triangles. The measure of a base angle of one of these triangles is about 85 degrees. What is the approximate measure of the vertex angle of the triangle?
recall that the sum of the angles of any triangle is 180°
You already have two of them, so getting the third should be no trouble, yeah?
To find the measure of the vertex angle of the isosceles triangle, we can use the fact that the sum of the angles in a triangle is 180 degrees.
Since the triangle has two congruent base angles, the sum of the base angles is 85 degrees + 85 degrees = 170 degrees.
To find the measure of the vertex angle, we subtract the sum of the base angles from 180 degrees:
180 degrees - 170 degrees = 10 degrees.
Therefore, the approximate measure of the vertex angle of the isosceles triangle is about 10 degrees.