Question

(a) Radius of the larger circle 10 cm
So, area of the larger circle = r2
= 3.14 x 10 x 10 = 314 cm?
(b) Radius of the smaller circle = 4 cm
Area of the smaller circle = ner2
= 3.14 x 4 x 4 = 50.24 cm?
(c) Area of the shaded region =(314- 50.24) cm² = 263.76 cm?
EXERCISE 11.3
23
22)
22
1. Find the circumference of the circles with the following radius: (Taken=
(a) 14 cm
(b) 28 mm
(c) 21 cm
2. Find the area of the following circles, given that:
22
(a) radius
= 14 mm (Take n =
(b) diameter = 49 n
7
(c) radius = 5 cm
3. If the circumference of a sheet is 154 m, find its radius. Also find the a
22
the sheet. (Take a =
7
4. A gardener wants to fence a circular garden of diameter 21m. Find the length
rope he needs to purchase, if he makes 2 rounds of fence. Also find the cost
22
rope, if it costs Rs 4 per meter. (Take n = 5)​

Answer 1

Answer:

Let the sides of right angles isosceles triangle be a,a,

2

a

The area of triangle is

2

1

a

2

=18

⇒a=6

The center of circumcircle of right angled isosceles triangle is center of hypotenuse

So the radius of circle is

2

6

=3

2

Therefore area of circle is π×3

2

×3

2

=18π

So the correct option is C