@jim_thompson5910
I got 519.05 for the lateral area , however that's not one of the pi choices..

Question

@jim_thompson5910 
I got 519.05 for the lateral area , however that's not one of the pi choices..

jim_thompson5910 · Answer

what is the radius of the new cone?

anonymous · Answer

r= 9 
h= 16 
Is what I plugged in

jim_thompson5910 · Answer

hint: you'll have a second cone that is similar to the first cone

jim_thompson5910 · Answer

"similar" as in "similar triangles" (the geometric definition of "similar")

jim_thompson5910 · Answer

|dw:1414976625040:dw|

solve for x

jim_thompson5910 · Answer

x is the radius of the larger new cone

anonymous · Answer

x= 12

jim_thompson5910 · Answer

now r = 12 and the slant height, call it s, is s = 16

|dw:1414976947964:dw|

jim_thompson5910 · Answer

what is the lateral surface area of this cone shown below (in terms of pi)?

|dw:1414977000151:dw|

anonymous · Answer

753.98

anonymous · Answer

@jim_thompson5910  There is no pi option for that answer...
There's only 653 :/

jim_thompson5910 · Answer

how did you get 653?

anonymous · Answer

No, my answer is above that comment.

jim_thompson5910 · Answer

how did you get 753.98 ?

anonymous · Answer

attachment

jim_thompson5910 · Answer

but we don't know h

jim_thompson5910 · Answer

the good news is that $\Large s = \sqrt{h^2 + r^2}$

jim_thompson5910 · Answer

so the formula reduces down to $\Large \pi*r*s$

anonymous · Answer

I thought that h=16 ?

jim_thompson5910 · Answer

no s = 16

jim_thompson5910 · Answer

go back to the drawing

|dw:1414977601271:dw|

jim_thompson5910 · Answer

we could find h and use the formula you posted, but that's extra unneeded work

jim_thompson5910 · Answer

|dw:1414977643434:dw|

jim_thompson5910 · Answer

height and slant height are 2 different things

anonymous · Answer

Oh! That's what confused me, I got 192pi .

jim_thompson5910 · Answer

which is the correct answer

anonymous · Answer

:)