The original expression is given by:

The correct way to rewrite the expression is given by:

For this, we use two properties:
Associative property:
The way of grouping the factors does not change the result of the multiplication:
Commutative property:
The order of the factors does not vary the product:
8/7 each side of the expression both go up by 1
3x7 + 2x3 = 22 + 6 = 28 is the area
A right angles is 90 degrees
if you mean 5/4 of the MEASURE of a right angle then
90 times 5/4 (because in math 'of' means multiply)
90 tmes 5/4=450/4=225/2=112.5 degrees