Question

The radius of circle whose circumference is equal to the sum of the circumference of two circles of diameter 36and20 cm is ?

Answer 1

Ur answer is in above attachment.

Answer 2

Formula :

Circumference = 2 π r

Given :

C of a circle is equal to the radius of 2 circle of diameters 36 and 20 cm

r₁ = 36 cm / 2

  = 18 cm   ...........................(1)

r₂ = 20 cm / 2

   = 10 cm   ..........................(2)      

Let radius of the circle be R

C = 2 π r₁ + 2 π r₂

==> 2 π R   = 2 π ( r₁ + r₂ )

==> Cancel 2 π both sides :

==> R = r₁ + r₂

==> R = 18 cm + 10 cm [ See (1) and (2) ]

==> R = 28 cm

The radius of the circle is 28 cm

Hope it helps :-)

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