Question

The circular portions of the following figures are
semicircles. For each of the following figures, find
(i) its perimeter,
(i) its area
(a)
21 cm
- 36 cm​

Answer 1

Step-by-step explanation:

semi circle

d= 21 cm

r= 21/2 cm

rectangle

l= 21 cm

b = 36-21= 15 cm

(i)

perimeter= 2× perimeter of semi circle 2 breadth

= 2× π r + 2×b

= 2× 22/7 × 21/2 + 2× 15

= 66+ 30

= 96 cm

(ii)

total area = 2×area of semi circle + area of rectangle

= 2×(πr^2)/2 + l×b

= π r^2 + l× B

= 22/7 × 21/2× 21/2 + 21×15

= 11×3×21/2+ 315

= 346.5+315

= 361.5 sq cm

Answer 2

step by step explanation:

for semi circle:

diameter = 21

radius =d/2

= 10.5

rectangle

= 36 - 21

= 15 breath

perimeter:

2 breath+ (3.14)r +(3.14)r

= 15+15+(3.14)(10.5)+(3.14)(10.5)

= 95.94

~ 96

Area:

Area of figure is = area of semi circle1+area of semi circle 2

+ area of rectangle

= (3.14) 10.5²/2 + (15*21)+ 3.14(10.5)²/2

=173.09 +315 +173.09

area of figure= 66.18 cm²