The perimeter of a rectangle of length 12 cm and breadth 16 cm is equal to the perimeter of a square and a semicircle whose diameter is equal to the side of a square then find the circumference of a semicircle?
The perimeter of a rectangle of length 12 cm and breadth 16 cm is equal to the perimeter of a square and a semicircle whose diameter is equal to the side of a square then find the circumference of a semicircle? Correct Answer 36 cm
Given:
Length of rectangle = 12 cm
Breadth of rectangle = 16 cm
Condition:
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The perimeter of a rectangle is equal to the perimeter of the square. ….. (1)
The diameter of the semicircle is equal to the side of the square. ………… (2)
Formula:
Perimeter of a rectangle = 2 × (l + b)
The perimeter of a square = 4 × side
Circumference of semicircle = πr + 2r
Diameter of semicircle = 2d
Calculation:
Let the length of a rectangle be 'l' cm and the breadth of a rectangle be 'b' cm and
Let ‘a’ be the side of the square
Now,
Perimeter of a rectangle = 2 × (12 + 16)
⇒ 2 × 28
⇒ 56 cm
Now,
The perimeter of a square = 4 × a
⇒ 4a
Now,
By using the above condition (1)
⇒ 56 = 4a
⇒ a = 56/4
⇒ a = 14 cm
Now,
By using the above condition (2)
Diameter of semicircle = 14 cm
Now,
Circumference of semicircle = 22/7 × 14/2 + 2 × 7
⇒ 22/7 × 7 + 14
⇒ 36 cm
∴ The circumference of the semicircle is 36 cm