A triangle has a perimeter of 91 yards. The first side is twice the length of the second side. The third side is seven yards longer than the second side. How long is each side?

The first side is:

The second side is:

The third side is:

The first side is: 42yd

The second side is: 21yd

The third side is: 28yd

Step-by-step explanation:

By using one variable and expressions for each side, we can set up an equation equal to the measure of the perimeter given to solve for the variable and all the other sides:

Second side = x

First side 'twice the length of the second' = 2x

Third side 'seven yards longer than the second' = x + 7

Perimeter is the sum of all the sides:

2x + x + x + 7 = 91

Combine like terms: 4x + 7 = 91

Subtract 7 from both sides: 4x + 7 - 7 = 91 - 7 or 4x = 84

Divide by 4: 4x/4 = 84/4 or x = 21

x = 21

2x = 21 (2) = 42

x + 7 = 21 + 7 = 28