Question

The perimeter of the triangle below is 125 units. Find the value of y.

4y + 2
5y
y + 3

Answer 1

We know the definition of perimeter is the sun of the lengths of all the sides, so we set it up as an addition problem.

Next, we combine the “like terms”, meaning all the terms with y, and all the numbers without a variable attached.

Then we solve for y by first subtracting 5 from both sides of the equal sign, then dividing 10 from both sides, leaving us with y = 12.

You can check your work by replacing y with 12 in the original equation. You will find that it all adds up to 125 units.