Question

I need help solving problem 11.

Answer 1

Since triangle ABC is isosceles, then angles 1 and 9 are congruent.

4x + 3 = 9x - 47

-5x = -50

x = 10

m<1 = 4x + 3 = 40 + 3 = 43

m<1 = m<9 = 43

Triangle DBE is equilateral, so it is also equiangular.

m< 4 = m<5 = m<6 =60

Angles 3 and 8 are supplementary to congruent angles that measure 60 deg, so 180 - 60 = 120, so

m<3 = m<8 = 120

For angles 2 and 7, use the sum of the measures of the angles of a triangle is 180 deg.

m<1 + m<2 + m<3 = 180

43 + m<2 + 120 = 180

m<2 + 163 = 180

m<2 = 17

m<2 = m<7 = 17