Question

If the area of rectangle is 128cm square and length is twice of breadth.Find it's length and breadth​

Answer 1

Given :

• Length of the rectangle is twice of its breadth.
• Area of the rectangle is 128 cm².

To find :

• Length and breadth of the rectangular.

Solution :

Consider,

• Length of the rectangle = x cm
• Breadth of the rectangle = y cm

According to the 1st condition :-

• Length is twice of its breadth.

$\to\sf{x=2y....................(i)}$

According to the 2nd condition :-

• Area of the rectangle is 128 cm².

$\to\sf{xy=128}$

$\to\sf{2y\times\:y=128\:[put\:x=2y\: from\:eq(i)]}$

$\to\sf{2y^2=128}$

$\to\sf{y^2=64}$

$\to\sf{y=\sqrt{64}}$

$\to\sf{y=8}$

• Breadth = 8 cm.

Now , put y = 8 in eq (i) for getting the value of x.

$\to\sf{x=2y}$

$\to\sf{x=2\times:8}$

$\to\sf{x=16}$

• Length = 16 cm.

Therefore , the length of the rectangle is 16 cm & the breadth of the rectangle is 8 cm.

Answer 2

Answer: let the breadth be=b

Let the length be=l

Area of rectangle=128cm²

Area of rectangle=l×b......1

According to question

l=2b.......2

Put value l in eq 1

Area of rectangle=l×b

128=2b×b

128=2b²

128/2=b²

64=b²

8cm=b

Now,put value of b in eq 2

l=2b

l=2×8

l=16cm