The base angle of an isosceles triangle is five more than twice the vertex angle. What is the base angle?

Answer 1

Draw and label a diagram!

v represents the vertex angle

2v + 5 represents one of the two base angles

v + 2(2v + 5) = 180

Can you solve for v and answer?

Answer 2

B= 2A+5

there are two base angles that are equal, since it's an isosceles triangle

isosceles triangles have 2 equal sides and 2 equal angles

2B+A = 180

substitute 2A+5 for B

2(2A+5)+A = 180

all triangles have 3 angles that sum to 180

4A+10 + A = 180

5A = 170

A =170/5

A = 34 degrees for the Apex Angle

B = (180-34)/2 = 146/2 = 73 degrees for each Base angle

2(73)+34 = 146+34 = 180