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The base area of a right circular cone is 1/4 of its total surface area. What is the ratio of the radius

to the slant height?

1 Answer

5 votes

Given:

The base area of a right circular cone is
(1)/(4) of its total surface area.

To find:

The ratio of the radius to the slant height.

Solution:

We know that,

Area of base of a right circular cone =
\pi r^2

Total surface area of a right circular cone =
\pi rl+\pi r^2

where, r is radius and l is slant height.

According to the question,


\pi r^2=(1)/(4)(\pi rl+\pi r^2)

Multiply both sides by.


4\pi r^2=\pi rl+\pi r^2


4\pi r^2-\pi r^2=\pi rl


3\pi r^2=\pi rl

Cancel out the common factors from both sides.


3r=l

Now, ratio of the radius to the slant height is


(r)/(l)=(r)/(3r)


(r)/(l)=(1)/(3)

Therefore, the ratio of the radius to the slant height is 1:3.

User Tehaaron
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