90=4(r)

Solution for 90=4(r) equation:

Simplifying
90 = 4(r)

Solving
90 = 4r

Solving for variable 'r'.

Move all terms containing r to the left, all other terms to the right.

Add '-4r' to each side of the equation.
90 + -4r = 4r + -4r

Combine like terms: 4r + -4r = 0
90 + -4r = 0

Add '-90' to each side of the equation.
90 + -90 + -4r = 0 + -90

Combine like terms: 90 + -90 = 0
0 + -4r = 0 + -90
-4r = 0 + -90

Combine like terms: 0 + -90 = -90
-4r = -90

Divide each side by '-4'.
r = 22.5

Simplifying
r = 22.5