AK = 640
Δ ABC and ΔFJK are similar. They are small triangles.
ΔCDF is the big triangle.
640 / 2 = 320 m= CF
AC & FK= 320/2 = 160 m each
2AC = CF = 2FK
2(160) = 320 = 2(160)
BG = 20 m
20/160 = x / 320
20*320 = 160x
6400 = 160x
6400/160 = x
40 = x
Area of CDF = (40 m * 320 m)/2 = 12,800 / 2= 6,400 m²
A "cross section" is basically the two-dimensional face that you get when you cut a three-dimensional figure a certain way. For example, imagine you're buttering your bread. When you cut a pat of butter off, what shape is left on the butter? A square!
So, imagine cutting a ball in half. What shape is left? A circle!
Answer: circle
- linear pairs are supplementary, meaning they add up to 180°
5x + 9 + 3x + 11 = 180
8x + 20 = 180
8x = 160
x = 20
- now plug in.
angle 1: 5(20) + 9 = 100 + 9 = 109°
angle 2: 3(20) + 11 = 60 + 11 = 71°