Question

The perimeter of a rectangle is 12 cm and it’s breadth is 2 cm. What will be it’s length?

(a) 2 cm

(b) 3 cm

(c) 4 cm

(d) 5 cm

I had been asked this question in class test.

The query is from Solving Linear Equations with Variables on Both the Sides in portion Linear Equations in One Variable of Mathematics – Class 8

Answer 1

Right answer is (b) 3 cm

To explain I would say: For any rectangle the formula for perimeter is 2 × (Length + Breadth). Here we already know the breadth of the rectangle. When we substitute the known values in the formula for perimeter of a rectangle we get,

12 = 2 × (Length + 2)

∴ 6 = Length + 2

∴ Length = 4 cm.