A triangle has a perimeter of 50. If two of the side lengths are equal and the third side is five more than the equal sides, what is the length of the third side?

15

23

20

35

Question

A triangle has a perimeter of 50. If two of the side lengths are equal and the third side is five more than the equal sides, what is the length of the third side?

15

23

20

35

Hero · Answer

Let x represent the length of the 1st side
and y represent the length of the 2nd side
and z represent the length of the 3rd side

Then x + y + z = 50
  and x = y since the first couple lengths are equal
  and z = x + 5 represents the length of the 3rd side since it is five more than both x and y.

so x + x + (x + 5) = 50

In short, 3x + 5 = 50

Solve for x. Take the result you find for x and add five more to get the length of the third side.