From a circular piece of paper of area 3850 cm2, an equilateral triangle of area 16√3 cm2 and a regular hexagon of area 486√3 cm2 is cut, then what percent of perimeter is cut from the circle?
From a circular piece of paper of area 3850 cm2, an equilateral triangle of area 16√3 cm2 and a regular hexagon of area 486√3 cm2 is cut, then what percent of perimeter is cut from the circle? Correct Answer 60%
Given:
Area of circle = 3850 cm2
Area of equilateral triangle = 16√3 cm2
Area of regular hexagon = 486√3 cm2
Formula used:
Area of circle = π × (radius)2
Area of equilateral triangle = √3/4 × (side)2
Area of regular hexagon = 3√3/2 × (side)2
Circumference of circle = 2 × π × radius
Perimeter of equilateral triangle = 3 × side
Perimeter of regular hexagon = 6 × side
Calculation:
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Let radius of circle, side of triangle and side of hexagon is ‘r’, ‘a’ and ‘b’ respectively.
Now,
πr2 = 3850
r = 35 cm
Perimeter of circle = 2πr
= 220 cm
√3a2/4 = 16√3
a2 = 64
a = 8
Perimeter of triangle = 3a = 24 cm
3√3b2/2 = 486√3
3b2/2 = 486
b2 = 324
b = 18
Perimeter of hexagon = 6a = 108 cm
Perimeter cut from the circle = 24 + 108 = 132 cm
∴ Required percentage = (132/220) × 100 = 60%