Question

The perimeter of the triangle below is 89 units. Find the length of side BC.

Write your answer without variables.

Answer 1

BC = 10 units

Explanation:

Perimeter of triangle:

Perimeter = Sum of all sides

y + 1 + 4y + 5y - 2 = 89 units

y + 4y + 5y + 1 - 2 = 89

Combine like terms,

10y - 1 = 89

Add 1 to both sides,

10y = 89 + 1

10y = 90

Divide both sides by 10,

y = 90 ÷ 10

y = 9 units

BC = y + 1

= 9 + 1

= 10 units