Answer:
8x !
Step-by-step explanation:
we know that
The formula of the surface area of the cone is equal to

where
SA is the surface area
r is the radius of the cone
l is the slant height
in this problem we have

Solve the formula for l

substitute the values

therefore
<u>the answer is</u>
The slant height is 
53/2 is 25.5 as a fraction; 40/2 is 20 as a fraction
We could use the numbers and the difference of the original cost - the end price in a equation.
53 × x/100 = 15.9
Cross multiply 100 × 15.9.
53x=1590
Divide both sides by 53.
x=30
The coupon was 30%
12 = 60 degrees.
The "C" pattern means that whatever is on the top/bottom corner will be equal to the opposite one.