What is the measure of the third angle of a triangle if one angle measures 15 degrees and the other measures 85 degrees?
The sum of the measures of the angles of a triangle is 180
degrees. First, calculate the sum of the two known angles. Then
subtract that result from 180. That difference is the measure of
the third unknown angle.
Given: One angle of a triangle is 15 degrees and the second
angle of the
triangle is 85 degrees.
To find: We need to find the third angle of the triangle.
Let the third angle of the triangle be x.
We know that the sum of the angles in a triangle is 180
degrees.
==> 15 degrees + 85 degrees + x degrees = 180 degrees.
==> 100 degrees + x degrees = 180 degress.
==> x = 180 degrees - 100 degrees.
==> x = 80 degress.
Therefore the third angle of the triangle is 80 degrees.