Question

8. Find the perimeter of the following figures which are shaded.
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Answer 1

1) so as we know,

perimeter of circle = 2πr

so here, this diagram have 4 half-circles .

diameter = 3

so, radius = 3 / 2

perimeter of half circle = 1/2 × 2πr

= πr

now , for half circle

perimeter of half circle = πr

= 22/7 × 3/2 ( r = 3/2 , because of diameter of circle = 3 )

= 33 / 7

number of half circle = 4

so, = 4 × 33 / 7

= 132 / 7

2) as we know

( for big circle ) perimeter of half circle = πr

= π × 1.4 [ d = 2.8 so r = 1.4 ]

= 22 / 7 × 14 / 10

= 44 / 10

= 4.4

( for two circle ) perimeter of half circle = πr

= 22 / 7 × 0.7

[ r = 0.7 because diameter of one small half circle = 1.4 so that's why r = 0.7]

= 22 / 7 × 7 / 10

= 2.2

here two half circles are appear so = 2 × 2.2 = 4.4 cm

so tatal perimeter = 4.4 + 4.4 = 8.8