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28 votes
28 votes
Given: m∠AKB = 25°

KO = 25

Find: V, Surface Area of of a cone

Please leave answers in term of Pi

User Mattdwen
by
2.6k points

1 Answer

18 votes
18 votes

Answer:

V = 255.98189 pi

SA = 172.64114π

Explanation:

The first thing to do is find the radius.

the measure of angle AKO = 1/2 the measure of angle AKB

m< AKO = 12.5 degrees

Now use trig to find AO (aka the radius)

tan(12.5) = AO/25

AO = 25* tan(12.5)

I'm leaving it like this to get a more accurate number

Now to find the volume

the volume of a cone is pir^2h/3

plugging everything in we get:

pi(25*tan(12.5))^2 * 25/3

which is about 255.98189 pi

Now for surface area

(this is the moment I realize symbols exist)

SA = πr(r+√h²+r²)

plugging everything in we have

π(25tan(12.5))((25tan(12.5)+√625+(25tan(12.5))^2)

I know it looks like a lot but that's mainly because I left the radius as 25tan(12.5)

The Surface Area is about 172.64114π

User Twoflower
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3.1k points