The sum of the area of two rectangles is 384 cm2 and the breadth of both rectangles is equal to the diameter of the circle whose area is 16π cm2. If the difference between the lengths of both rectangles is 24 cm, then, find the sum of the perimeter of both rectangles (in cm)?

The sum of the area of two rectangles is 384 cm2 and the breadth of both rectangles is equal to the diameter of the circle whose area is 16π cm2. If the difference between the lengths of both rectangles is 24 cm, then, find the sum of the perimeter of both rectangles (in cm)? Correct Answer 128

Given:

Sum of area of both rectangle = 384 cm2

Breadth of both rectangle = Diameter of the circle

Sum of length of both rectangle = 48 cm

Formula Used:

Area of rectangle = length × breadth

Perimeter of Rectangle = 2(length + breadth)

Area of circle = πr2

Perimeter of circle = 2πr

Calculation:

Suppose the length of both rectangle is x and y, respectively.

The area of the circle = πr2 = 16π

⇒ r2 = 16

⇒ r = 4 cm

The diameter of circle = 8 cm which is equal to breadth of the rectangle.

Sum of the area of both rectangle = 384 cm2

⇒ 8x + 8y = 384

⇒ x + y = 48 cm      ---(i)

Now, the difference between the lengths of the both rectangles = 24 cm

⇒ x – y = 24 cm      ---(ii)

Add both equation (i) and (ii), we have –

⇒ 2x = 72

⇒ x = 72/2

⇒ x = 36 cm

Put this value in the equation (i), we have –

⇒ 36 + y = 48

⇒ y = 12 cm

Therefore, perimeter of the first rectangle = 2(x + 8) = 2(36 + 8)

⇒ 2(44)

⇒ 88 cm

Perimeter of the second rectangle = 2(y +8)

⇒ 2(12 + 8)

⇒ 2(20)

⇒ 40 cm

The sum of the perimeter of both rectangle = (88 + 40) cm

⇒ 128 cm

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