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In a cone, the radius is 8 cm and the lateral surface area is 136pi cm^2.

1. find the slant height of the cone.

2.Find the height of the cone.

3.Find the volume of the cone, in terms of pi.

 Apr 24, 2016

Best Answer 

 #1
avatar+118723 
+10

In a cone, the radius is 8 cm and the lateral surface area is 136pi cm^2.

1. find the slant height of the cone.

2.Find the height of the cone.

3.Find the volume of the cone, in terms of pi.

 

The lateral surface area of a cone is given by the formula  pi*r*L   where L is the slant height.

 

\(Lateral\; Surface\; area=\pi rl\\ 136\pi = \pi \times 8 \times l\\ 136=8 \times l\\ 17=l\\ slant\;height=17\;cm \)

 

 

The radius is 8cm and the slant height is 17cm

so

\(h^2=17^2-8^2\\ h^2=289-64\\ h^2=225\\ h=15\; cm\)

 

A cone is a circular pyramid and the volume of any pyramid is   V = (1/3) * area of base * perpendicular height

\(Area \;of \;base = \pi*r^2 = \pi * 8^2 = 64\pi\)

 

\(V=\frac{1}{3}*64\pi*15\\ V=64\pi*5\\ V=320\pi\;\;cm^3\\\)

 Apr 24, 2016
 #1
avatar+118723 
+10
Best Answer

In a cone, the radius is 8 cm and the lateral surface area is 136pi cm^2.

1. find the slant height of the cone.

2.Find the height of the cone.

3.Find the volume of the cone, in terms of pi.

 

The lateral surface area of a cone is given by the formula  pi*r*L   where L is the slant height.

 

\(Lateral\; Surface\; area=\pi rl\\ 136\pi = \pi \times 8 \times l\\ 136=8 \times l\\ 17=l\\ slant\;height=17\;cm \)

 

 

The radius is 8cm and the slant height is 17cm

so

\(h^2=17^2-8^2\\ h^2=289-64\\ h^2=225\\ h=15\; cm\)

 

A cone is a circular pyramid and the volume of any pyramid is   V = (1/3) * area of base * perpendicular height

\(Area \;of \;base = \pi*r^2 = \pi * 8^2 = 64\pi\)

 

\(V=\frac{1}{3}*64\pi*15\\ V=64\pi*5\\ V=320\pi\;\;cm^3\\\)

Melody Apr 24, 2016

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