You can see by the image how did I get the answer
1. The surface area of a cone S is S=

, where r is the radius of the base and l is the slant height.
2. The slant height l is found as follows:



3.


4. The answer is C
Answer:
y = 2/4x -2
Step-by-step explanation:
Hey there!
Apply fraction cross multiply: if a/b = c/d , then a *d = b*c
2 ( 5x - 2 ) = ( 2x + 4 ) * 4
expand : 2 (5x-2 ) => 2*5x - 2*2 => 10x - 4
expand : ( 2x +4 ) * 4 => 2x * 4 + 4*4 => 8x + 16
10x - 4 = 8x+16
add 4 to both sides:
10x-4+4 = 8x+16+4
simplify :
10x = 8x + 20
subtract 8x from both sides:
10x -8x = 8x+20-8x
simplify:
2x = 20
Therefore:
x = 20 / 2
x = 10
Hope that helps!