I Need help solving this area problem.
@mathstudent55
@ganeshie8

Question

I Need help solving this area problem.
@mathstudent55 
@ganeshie8

anonymous · Answer

First find the circumference of the circle base

anonymous · Answer

Now, draw a triangle, the base of the triangle is the same length of the circumference. The other 2 legs are a length of 20

anonymous · Answer

Then use Heron's formula to find the area of a triangle.

mathstudent55 · Answer

$\large LA_{cone} = \pi r L$

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anonymous · Answer

so it would be 2*pi*9 = 56.54
C= 56.548 aprx. 54.55  
?

mathstudent55 · Answer

The lateral surface area of a cone is the product of the radius of the base, pi, and the slant height.
In the figure above, L is the slant height.

mathstudent55 · Answer

Where are you getting the 2 from?

anonymous · Answer

Circumference formula?

mathstudent55 · Answer

All you need is this:
pi * r * L

anonymous · Answer

565.486 or .49

mathstudent55 · Answer

I'd say 565.5

anonymous · Answer

Therefore, it's D. 565. 7 ...
Idk where their .7 came from?

mathstudent55 · Answer

Me neither, but that is the closest answer by far.

anonymous · Answer

Thank you :)

mathstudent55 · Answer

wlcm