right angle triangle

Question

if a right angled triangle has the hypotenuse represented by (2x-7)cm, the bottom by x cm, and (x +5)cm on the back side,

 

how do you show that the perimeter P cm of the above triangle is given by P=4x-2

 

and if the perimeter is 82cm, calculate the value of x.

Answer 1

Well perimeter is the addition of all the side lengths of the shape.  So you just add them together.

 

P = (2x-7) + x + (x+5) = 4x - 2

 

If P is 82, then you can calculate x:

 

82 = 4x-2

84 = 4x

x = 21