SOLUTION: From a rectangle , corner is cut in triangular shape to give a pentagon . The length of the sides are 13,19,20,25 and 31 in cm . lengths are not in order . find the area of the pen

Algebra ->  Surface-area -> SOLUTION: From a rectangle , corner is cut in triangular shape to give a pentagon . The length of the sides are 13,19,20,25 and 31 in cm . lengths are not in order . find the area of the pen      Log On


   



Question 336572: From a rectangle , corner is cut in triangular shape to give a pentagon . The length of the sides are 13,19,20,25 and 31 in cm . lengths are not in order . find the area of the pentagon.
______
|...........\
|............\ -----> approximate shape
|_______|

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
From a rectangle , corner is cut in triangular shape to give a pentagon .
The length of the sides are 13,19,20,25 and 31 in cm . lengths are not in order
. find the area of the pentagon.
:
I assigned the dimensions as follow:
starting with the hypotenuse of the triangle = 13
the remaining part of that side = 19
bottom = 25
vert side = 31
top = 20
:
Find the area of the rectangle without the triangle removed
25 * 31 = 775
:
The triangle dimensions: 5 by 12 by 13,
prove it is a right triangle: sqrt%285%5E2%2B12%5E2%29 = 13
A = .5 * 5 * 12 = 30
:
Pentagon area: 775 - 30 = 745