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a square pyramid has the base length of 10 cm. The slant height of the pyramid is 13 cm what is the volume?

 Apr 13, 2015

Best Answer 

 #1
avatar+23254 
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The volume of a pyramid can be found by:  V  =  (1/3)x(Area of the base)x(height)

Since its base is a square with side length of 10, the area of the base is 10x10 = 100.

To find the height:  A right triangle is formed from the top point to the center of the base and then out to the middle of a side and then back to the top point.

The distance from the center of the base to the middle of a side is 5.

The distance from the middle of a side to the top point is 13 (and this is the hypotenuse of the right triangle).

Using the Pythagorean Theorem:  a2 + b2  =  c2  --->   a2 + 52  =  132

Solving this for a:  a  =  12   --->  the height =  12.

So:  V  =  (1/3)(100)(12)  =  ...

 Apr 14, 2015
 #1
avatar+23254 
+5
Best Answer

The volume of a pyramid can be found by:  V  =  (1/3)x(Area of the base)x(height)

Since its base is a square with side length of 10, the area of the base is 10x10 = 100.

To find the height:  A right triangle is formed from the top point to the center of the base and then out to the middle of a side and then back to the top point.

The distance from the center of the base to the middle of a side is 5.

The distance from the middle of a side to the top point is 13 (and this is the hypotenuse of the right triangle).

Using the Pythagorean Theorem:  a2 + b2  =  c2  --->   a2 + 52  =  132

Solving this for a:  a  =  12   --->  the height =  12.

So:  V  =  (1/3)(100)(12)  =  ...

geno3141 Apr 14, 2015

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