A rectangle is 3 times as long as it is wide. Its perimeter is 80 centimeters. Find its deminsions.
I dont know how to set it up with variables. Someone please help.
Ok. You can define a side as "$\displaystyle x$". The opposite side will have a length of $\displaystyle x$ too. You are told that the 2 other sides are 3 times longer. It means their values are $\displaystyle 3x$.
Also, we know that the perimeter is 80 cm. You can put the equation of the perimeter adding the four sides together, we get $\displaystyle 3x+3x+x+x=80$. I let you solve for x, that is the answer.