Triangle ABC is isosceles with angle B congruent to angle C. The measure of angle C is four times the measure of angle A plus 9 degrees. What is the number of degrees in the measure of angle B?
Is there a graph?
Let the measure of angle A = x
And the measures of angle B and C = 4x + 9
So
A + B + C =180 .......so.....
x + (4x + 9) + (4x + 9) = 180 simplify
9x + 18 =180
9x =180 - 18
9x = 162
x = 162 / 9 = 18
So...angle B = angle C = 4 (18) + 9 = 81°
