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I have a pentagon with side length 7, and I need to know the area. Any help?

 Apr 19, 2017

Best Answer 

 #1
avatar+9479 
+2

 

 

area of pentagon = 10 * area of third triangle

 

area of third triangle = (1/2) * base * height

area of third triangle = (1/2) * 3.5 * (3.5 / tan 36º)

area of third triangle = 6.125 / tan 36º

 

area of pentagon = 10 * 6.125 / tan 36º

area of pentagon = 61.25 / tan 36º

area of pentagon ≈ 84.303 square units

 

*edit*

as long as this is a regular pentagon! :)

 Apr 19, 2017
edited by hectictar  Apr 19, 2017
 #1
avatar+9479 
+2
Best Answer

 

 

area of pentagon = 10 * area of third triangle

 

area of third triangle = (1/2) * base * height

area of third triangle = (1/2) * 3.5 * (3.5 / tan 36º)

area of third triangle = 6.125 / tan 36º

 

area of pentagon = 10 * 6.125 / tan 36º

area of pentagon = 61.25 / tan 36º

area of pentagon ≈ 84.303 square units

 

*edit*

as long as this is a regular pentagon! :)

hectictar Apr 19, 2017
edited by hectictar  Apr 19, 2017

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