Answer:
Correct choice is B
Step-by-step explanation:
In step 4 were proved that 
By definition, similar triangles have proportional lengths of corresponding sides. To the side AB corresponds side ED, to the side AC corresponds side DC and to the side BC corresponds side EC. Thus,

Radius=8/2=4cm
volume=4*4*3.14*20=1004.8
The answer is 1004.8cm₃
The reciprocal of 7 is 1/7, reciprocal of 8 is 1/8, and reciprocal of 9 is 1/9
Answer:
I don't know if it's correct
but I tried
Step-by-step explanation:
let the angle be x
20+4x+x=180
20+5x=180
5x=160
x=32