Question

If the perimeter of a triangle is 9x + 7y and two of the sides are 2x + 3y and 4x − y, which is the third side?

Answer 1

To find the third side of the triangle, subtract the sum of the lengths of the two given sides from the perimeter:

Third side = Perimeter - (First side + Second side)

Third side = (9x + 7y) - ((2x + 3y) + (4x - y))

Third side = 9x + 7y - 2x - 3y - 4x + y

Third side = (9x - 2x - 4x) + (7y - 3y + y)

Third side = 3x + 5y

So, the third side of the triangle is 3x + 5y.