Question

7. If the perimeter of a semi-circular
protractor is 66 cm, the diameter of the
protractor is
​

Answer 1

Answer:

circumference of semi circle = 1/2 2πr

66 = 1/2 × 22/7 × r

66 = 11/7×r

r = 66×7/11

r = 6 × 7

= 42 is the radius

2 × radius = diameter

42 × 2

= 84

Answer 2

Answer:

perimeter of semi circle =

$\pi \times radius + diameter$

so, 66=22/7+ x ✖ 2x ( let the radius as x then diameter will be 2x )

66 ✖ 7/22 = 3x

21=3x

21/3=x

7=x

thus radius = x = 7

if radius is 7 so diameter will be 14cm

Step-by-step explanation:

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