SOLUTION: The base of an isosceles triangle is one-third the length of each of the congruent sides. The perimeter of the triangle is 84 cm. How long is the base?

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: The base of an isosceles triangle is one-third the length of each of the congruent sides. The perimeter of the triangle is 84 cm. How long is the base?      Log On


   

Question 161696: The base of an isosceles triangle is one-third the length of each of the congruent sides. The perimeter of the triangle is 84 cm. How long is the base?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Calls the sides S
Call the base B
The perimeter is then S+%2B+S+%2B+B
S+%2B+S+%2B+B+=+84
It is given that
B+=+%281%2F3%29%2AS, so
S+%2B+S+%2B+%281%2F3%29%2AS+=+84
Multiply both sides by 3
3%2A2%2AS+%2B+S+=+252
7S+=+252
S+=+36
B+=+%281%2F3%29%2AS
B+=+%281%2F3%29%2A36
B+=+12cm
check:
S+%2B+S+%2B+B+=+84
36+%2B+36+%2B+12+=+84
84+=+84
OK