Question

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.​

Answer 1

Answer:

28 cm

Radius of 1st Circle = R¹ and of 2nd Circle = r²

Answer 2

Given :

• Radius of two circle :-
• Radius₁ = 19 cm
• Radius₂ = 9 cm

To find :

• Radius of the circle which has circumference equal to the sum of the circumference of the two circles.

Concept Used :

→ Formula of circumference of circle :-

• Circumference of circle = 2πr

where,

• Take π = 22/7
• r = radius of the circle

Solution :

According to the question,

⇒ 2πr₁ + 2πr₂ = 2πR

⇒ Take 2π common from both the sides.

⇒ 2π(r₁ + r₂) = 2π(R)

⇒ 2π gets cancelled.

⇒ r₁ + r₂ = R

⇒ 19 + 9 = R

⇒ 28 = R

Radius of the circle which has circumference equal to the sum of the circumference of the two circles = 28 cm

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Know MorE :

• Area of circle = πr²
• Diameter = 2 × Radius
• Radius = Diameter/2
• Surface area of sphere = 4πr²
• Volume of cylinder = πr²h
• Volume of cone = 1/3 πr²h
• Curved surface area of cone = πrl
• Total surface area of cone = πrl + πr²h
• Total surface area of cylinder = 2πrh + 2πr²