Question

6. The circular portions of the following figures are
semicircles. For each of the following figures, find
() its perimeter,
) its area.
​

Answer 1

Answer:

Perimeter of larger semi circle=

$\pi \: r$

=3.14×9

=28.26cm

Perimeter of 1 small semi circle=

$\pi \: r$

=3.14×4.5

=14.15

Now perimeter of 2 small semi circle of radius 4.5

=14.15×2

=28.3cm

THEREFORE perimeter of the adjoining figure=

=PERIMETER OF LARGER+PERIMETER OF TWO SMALLER SEMI CIRCLE

=28.26+28.3

=56.56cm

Area of larger semi circle

$\frac{\pi {r}^{2} }{2}$

=3.14×9×9÷2

=127.17cm^2

Area of 1 small semi circle.

$\frac{\pi {r}^{2} }{2}$

=3.14×4.5×4.5÷2

=31.7925cm^2

Area of 2 small semi circle of radius 4.5cm

=31.7925×2

=68.585cm^2

THEREFORE AREA OF THE ADJOINING FIGURE

=AREA OF LARGER + AREA OF TWO SMALLER SEMI CIRCLE

= 127.17+68.585

=195.755cm^2