The equation can be modeled as
X + X + (X+4) = 61
X is used for all because they are all the same number and can be given the same variable
The third is given plus four so we can use a common variable
3x + 4 = 61
3x = 57 (subtracted four)
x = 19 (divided by three)
Solving for third side so x + 4
The third side is 23 inches
