In a certain triangle, the longest side is 1 foot longer than the second longest side, and the second-longest side is 1 foot longer than the shortest side. If the perimeter is 21 feet, how many feet long is the shortest side?

x = shortest side

x + 1 = second-longest side {second-longest side is 1 ft longer than shortest side}

x + 2 = longest side {longest-side is 1 ft longer than second-longest side}

Perimeter is the distance around the outside of an object.

x + x + 1 + x + 2 = 21 {added up all sides and set equal to 21}

3x + 3 = 21 {combined like terms}

3x = 18 {subtracted 3 from each side}

x = 6 {divided each side by 3}

**6 ft is the shortest side**

*- Algebra House*