CD=21
DE=16
CE=21#7:
(3x-4)+(9x+17)+(6x-31)=180 <- sum of angles in a triangle
18x-18x=180 <- Simplify
18x=198
x=11 now substitute, m<A=9*11+17, m<A=116
#8:
(10x-23)=(7x-26)+(5x-27) <- Exterior angle of triangle
10x-23=12x-53
x=30; substitute, m<A=30*5-27, m<A=123
#9:
m<R=74 <- Base angles therom
m<Q+74*2=180 <- Sum of angles in triangle
m<Q=32 <- Simplify
#10:
m<E=m<G <- Base angles therom
2m<E+106=180 <-Sum of angles in triangle
m<E=m<G=37
#11:
m<A=180-48*2
m<A=84
Triangle is isosceles so by base angles therom, AC=9 ft
#12
m<M=m<N=m<P=60 <- Triangle is equilateral
#13
2(8x-23)+34=180 <- Sum of angles in triangle
16x-12=180
16x=192
x=12
#14
3(9x-3)=180 <- Su, of angles in triangle
9x-3=60
9x=63
x=7
#15
4x+9=16x-27 <- Legs of isosceles triangle
12x=36
x=3
Now substitute
