Perimeter is the sum of all the lengths of the figure. Since the perimeter is 25, make the sum of the sides equal to 25 in an equation.
7 + t + 10 - t + 4t - 11 + t - 1 = 25
Combine like terms.
5 + 5t = 25
Subtract 5 from both sides.
5t = 20
Divide both sides by 5.
t = 4
