Question Details

The perimeters of two circular fields C1 and C2 are 40π m and 96π m, respectively. What is the radius of the third circular field C3 whose area is equal to the sum of the areas of C1 and C2 ?

Options

A

68 m

B

51 m

C

52 m

D

53 m

Show Answer

Correct Answer :

Option C

52 m

Solution :

The correct answer is 52 m.


Let the radii of the two circular fields C1 and C2 be r1 and r2, respectively.


Step 1: Find the radii r1 and r2 using their perimeters.

The perimeter (circumference) of a circle is given by the formula:

Perimeter=2πr

For field C1, the perimeter is 40π m:

2πr1=40π

r1=20 m


For field C2, the perimeter is 96π m:

2πr2=96π

r2=48 m


Step 2: Calculate the areas of fields C1 and C2.

The area of a circle is given by the formula:

Area=πr2

Area of C1 (A1):

A1=π(20)2=400π m2

Area of C2 (A2):

A2=π(48)2=2304π m2


Step 3: Find the radius of field C3.

Let R be the radius of field C3. The area of C3 (A3) is equal to the sum of the areas of C1 and C2:

A3=A1+A2

πR2=400π+2304π

πR2=2704π

Dividing both sides by π:

R2=2704

R=2704=52 m


Thus, the radius of the third circular field C3 is 52 m.

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