Question

(a) If the breadth of rectangle in one-third of its length and perimeter is 80 cm, find the length and breadth of rectangle. ​

Answer 1

width = 10, length = 30

Explanation:

the perimeter can be written as: (2 x width)(2 x length) or width + width + length + length, I'm sure there are others, but I won't get into that.

anyways, lets call width of the triangle "x". x is 1/3 of the length, in other words, x + x + x = length. we can now say that length is 3x.

width = x

length = 3x

now lets plug in these answers to the "width" and "length" in the perimeter formula

perimeter = x + x + 3x + 3x

we are given the perimeter, that is 80.

x + x + 3x + 3x = 80

x + x can be simplified to 2x

think of "x" like label, say... xylophones

2 xylophones + 3 xylophones + 3 xylophones = 8 xylophones

8x = 80

divide 80 by 8.

x = 10

now we know the width.

width = 10

remember, the length is width x 3

10 x 3 = 30

the width = 30

let's check our answer!

10 + 10 + 30 + 30 = 80

Answer 2

Length = 30m and Breadth = 10m

Step-by-step explanation:

Given that :

Perimeter = 80 m ;

Breadth = 1/3 of Length ; Length = l

We know that :

Perimeter of rectangle = 2 ( L + B ).

80 = 2 ( L + 1/3 L )

80/2 = 4/3 L.

40 = 4/3 L

3/4 × 40 = L.

3 × 10 = L.

L = 30m.

Breadth = 1/3 of Length.

Breadth = 1/3 × 30.

Breadth = 10m.