The answer is A, 75 degrees
add all like terms
2x+196
all triangles equal 180 degrees
2x+196=180
subtract the 196 from 180
2x= -16
divide
x= -8
plug into angle A
-8+83
A=75
If P <span>is the midpoint of DE then
DE = 2(DP)
10x - 12 = 2(3x + 2)
10x - 12 = 6x + 4
10x - 6x = 4 + 12
4x = 16
x = 16/4
x = 4
DP = 3x + 2 = 3 * 4 + 2 = 12 + 2 = 14 units</span>
Easy and fast way to do it:
Go to google and type, " volume of a cone calculator" and type in the radius and height.
1/4;2/5;83/100;3/2;7/10;4/5