Formula for the area of a rectangle:
A = lw (A = area l = length(longest side) w = width(shortest side))
You know:
w = 3 1/2 or 3.5
A = 17 1/2 or 17.5 So substitute/plug it into the equation
A = lw Plug in 3.5 into "w" since w = 3.5, and 17.5 into "A" since A = 17.5
17.5 = l(3.5) To find l, isolate/get the variable "l" by itself in the equation. Divide 3.5 on both sides to get "l" by itself
[tex]\frac{17.5}{3.5} =\frac{l(3.5)}{3.5}[/tex]
5 = l The length is 5 in
PROOF
A = lw Plug in 3.5 into "w" and 5 into "l"
A = 5(3.5)
A = 17.5 in²
