Area/Perimeter of Circle

Chapter 12 Class 10 Areas related to Circles
Concept wise

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### Transcript

Ex 12.1, 1 The radii of two circles are 19 cm and 9 cm respectively. Find the radius of the circle which has circumference equal to the sum of the circumferences of the two circles. Given that, Radius of 1st circle = r1 = 9 cm Radius of 2nd circle = r2 = 19 cm Let the radius of required circle = r cm According to question, Circumference of required circle = Sum of circumference of two circles Now, Circumference of required circle = Sum of circumference of two circles 2πr = 18π+38π 2πr = 56 π r = 56π/2π r = 28 Hence, radius of new circle = r = 28 cm

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#### Davneet Singh

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