Question

The perimeter of an isosceles triangle is 29 feet. If the base measures 15 feet what is the measure of the other two sides?

Answer 1

They each equal `7` feet.

Explanation:

The equation for the perimeter of a triangle is `P=S_1+S_2+S_3`,
which for an isosceles triangle could be written as: `P=S_1+2(S_2)`
We know the perimeter is `29` feet, and the base is `15` feet. So we can substitute in those values to get:

`=>` `29=15+2(S_2)`

Subtract `15` from both sides, and get:

`=>` `14=2(S_2)`

Divide by `2`, and get:

`=>` `7=S_2`

Since `S_2=S_3`, we know that both sides equal `7` feet, which makes since, as it is an isosceles triangle and `7+7+15=29`.