Find the perimetre of semi-circle plate of radius 3.85 cm.
Answers
Radius = 3.85 cm.
Perimeter of semicircle = ( πr + 2r )
=> r ( π + 2 )
=> 3.85 × ( 22/7 + 2 )
=> 3.85 × ( 22 + 14/7)
=> 3.85 × ( 36/7)
=> ( 3.85 × 36)/7
=> 19.8 cm
Circumference = 2πr
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STEP 1: Find the length of the arc of the semi-circle plate:
circumference = 2π(3.85) cm
We divide circumference by 2 to get the length of the arc of the semi-circle:
semi-circle arc = π(3.85) cm
semi-circle arc = 12.10 cm
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STEP 2: Find the perimeter of the semi-circle plate:
The perimeter is the length of the arc + 2 of its radius:
Perimeter = 12.10 + 3.85 + 3.85 = 19.8 cm
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Answer: The perimeter of the semi-circle plate is 19.8 cm