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

1 Answer
Mar 25, 2018

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.