Answer:
Yes, it is a right triangle.
Step-by-step explanation:
a^2+b^2=c^2
The longest side is the hypotenuse so c^2 would be 90.
72^2+54^2=90^2
72 and 54 can be either a or b.
Solve for all exponents: 5184+2916=8100.
That equation is true, so the triangle is a right triangle.
Answer:
Perimeter 
Step-by-step explanation:
Let
= width of the rectangle.
From the information "length of a rectangle is 5cm more than width", we can write:
Length = 
- - - -
Perimeter
(formula for the perimeter of a rectangle)



∴ The expression of the perimeter of the rectangle in terms of
is
.
Hope this helps :)