Question

find the circumference of both circle ..( R means Radius )​

Answer 1

Answer:

88cm and 132 cm

Step-by-step explanation:

small circle

r=14cm

circumference=2πr

=2×22/7×14

=2×22×2

=88cm

large circle

r=21

circumference= 2×22/7×21

=44×3

=132 cm

Answer 2

Given: THERE ARE TWO CONCENTRIC CIRCLES IN WHICH THE RADIUS OF THE BIGGER CIRCLE IS 21 cm AND THE RADIUS OF THE SECOND CIRCLE WE DON'T KNOW.

To Find : THE CIRCUMFERENCE OF BOTH THE CIRCLES.

Solution :

The radius of the larger circle is 21 cm.

we know the formula for the circumference of a circle: 2πr

So the circumference of the larger circle is - 2*22/7*21 cm [ π = 22/7 or 3.14]

                                                                        = 132 cm

Now let us find the circumference of the inner circle,

we know that the radii of a circle are equal.

r = 21cm(given)

and a part of it is 7 cm.

so the radius of the inner circle is 21-7=14

Therefore, the circumference of the inner circle is  2πr,

                                                                                   2*22/7*14 = 88cm

hope you understand.

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