Question

A semicircular portion is cut out from a larger semicircle to form the given figure, where radius of unshaded region is 10.5 cm and radius of shaded region is 9.8cm.find the circumference of the shaded region. pi=22/7​

Answer 1

Answer:

The circumference of shaded region is 30.77 cm

Step-by-step explanation:

Given as :

For semicircular figure

The radius of un shaded region = r = 10.5 cm

The radius of shaded region = R = 9.8 cm

Let The circumference of shaded region = x cm

According to question

∵ circumference of semicircle = π × radius

So,  circumference of shaded region =  π × R

Or, x =  π × 9.8 cm

∴   x =  3.14 × 9.8 cm

i.e x =  30.77 cm

So,  circumference of shaded region =  x = 30.77 cm

Hence, The circumference of shaded region is 30.77 cm  Answer

Answer 2

Answer is : 58.2 cm

STEP:1

The diameter of the larger circle =10.5 cm+9.8 cm=20.3 cm.

The circumference of the larger semi-circle =πr=πd2.

Therefore, the circumference of the larger semi-circle =12×227×20.3=31.9 cm.

STEP:2

The circumference of the smaller semi-circle =12×227×10.5=16.5 cm.

So the circumference of the shaded region:  = circumference

of the larger semi-circle + circumference of the smaller semi-circle +9.8 cm

=31.9+16.5+9.8

Answer is : 58.2 cm

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