Posted by tyyyyyy on .
The perimeter of a triangle is 72 cenimeters.the second side is twice as long as the first side.the third side is four centimeters shorter than the second side.how long is the first side?

algebra 1 
drwls,
Let the first side length be A, etc.
A + B + C = 72
B = 2A
C = B4
B/2 + B + (B 4) = 2.5 B 4 = 72
2.5 B = 76
B = 30.4
A = 15.2 is the first side length
C = 26.4

Sum = 72, as required