Question

the retio of the circumference of two cricle is 3:1 if the circumference if figger cricle is 39.36 cm the redius of the smaller cricle is​

Answer 1

Given :

• Ratio of circumference of two circle = 3:1
• Circumference of bigger circle = 39.36 cm

To find :

Radius of smaller circle

Formula used :

• Circumference of circle = 2π × radius

Solution :

It is given that ratio of circumference of two circle is 3:1

➝ Circumference of bigger circle : Circumference of smaller circle = 3 : 1

$\sf \implies \dfrac{Circumference \: of \: bigger \: circle }{ Circumference \: of \: smaller \: circle}\:= \dfrac{3}{ 1}$

$\sf \implies \dfrac{39.36 \: cm}{ Circumference \: of \: smaller \: circle}\:= \dfrac{3}{ 1}$

$\sf \implies \dfrac{39.36 \: cm}{ 3}\:= Circumference \: of \: smaller \: circle$

$\sf \implies Circumference \: of \: smaller \: circle \: = \: 13.12 \: cm$

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Let , r be radius of smaller circle

Therefore, circumference of smaller circle = 2πr

$\sf \implies 2\pi \: r \: = \: 13.12 \: cm$

$\sf \implies \: r \: = \: \dfrac{13.12 \: cm}{2\pi}$

$\sf \implies \: r \: = \: \dfrac{6.58 \: cm}{3.14}$

$\sf \implies \: \bold{r \: = \: 2.1\: cm}$

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ANSWER :

Radius of smaller circle = 2.1 cm

Answer 2

$\huge\colorbox{pink}{Question࿐ }$

If the ratio of the circumference of two circles is 3:1, then find the ratio of their areas.

$\huge \underbrace \bold \blue {↓Solution↓}$

★ GEOMETRY [ CIRCLES ] ★

Given that the ratio of circumference of two circles is 3:1

Let the radius of two circles be m and n

2πm : 2πn = 3 : 1

Hence, m : n = 3 : 1

Ratio of areas of the circles will be ,

2πm² : 2πn² = m² : n² = 9 : 1

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