Question

The perimeter of an isosceles triangle is 13 cm. The side which is not equal to the other two sides has a length of 3 cm. What is the length of one of the sides which is equal?

• A. 10
• B. 5
• C. 7
• D. 2

Answer 1

The correct option is B

5

Subtracting the length of the non-equal side from the perimeter of the triangle will give us the total length of the two equal sides. We can divide this length by 2 to get length of each side.

Perimeter of the isosceles triangle = 13 cm.
Length of non-equal side = 3 cm.
Let the length of one of the equal sides be $xcm$.
Now, $xcm$ + $xcm$ + $3cm$ = $13cm$.
$2x+3=13$
$2x=13-3$
$2x=10$
$\therefore$ $x=5cm.$