Question

The diameters of two circles are in the
ratio 1:3. Find the ratio of their
circumference and areas.​

Answer 1

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Given :-- The diameters of two circles are in the

The diameters of two circles are in theratio 1:3.

Solution :---

r1 : r2 = 1 : 3

[i]The circumference ratio of two circles are

=》 2 ×22/7 × 1 : 2× 22/7 × 3

=》 1 : 3 . (Answer).

[ii] The area ratio of two circles are

=》 22/7 × 1^2 : 22/7 × 3^2

=》 1 : 9. ( Answer).

Answer 2

Answer:

Let the diameter of one circle=x

and the another circle=3x

therefore, radius of one circle=diameter/2

=x/2

radius of another circle =3x/2

circumference of a one circle = 2×22/7×x/2

= 22x/7

circumference of another circle =2×22/7×3x/2

= 66x/7

ratio of the circumference of two circles = (22x/7)/(

(66x/7)

=1/3

area of one circle=22/7×(x/2×x/2)

=11x×x/14

area of another circle =22/7×(3x/2×3x/2)

=99x×x/14

ratio of the area of two circle =(11x×x/14)/(99x×x/14)

=1/9

ratio of the circumference to the area of circle

=(1/3)/(1/9)

=3/1

=3:1