Question Details

A sector with radius 12 cm has area 132 cm2. Find the central angle.

Options

A

105°

B

110°

C

115°

D

120°

Show Answer

Correct Answer :

Option A

105°

Solution :

The correct option is 105°.

To find the central angle of the sector, we use the standard formula for the area of a sector of a circle:

Area of sector=θ360°×πr2

From the given question, we have the following values:
Radius of the sector, r=12 cm
Area of the sector =132 cm2
Using π=227

Now, substitute these given values into the area formula:

132=θ360°×227×122

Simplify the square of the radius:

132=θ360°×227×144

Rearrange the equation to solve for the central angle θ:

θ=132×360°×722×144

Simplify the terms step-by-step:
Divide 132 by 22:

13222=6

Now substitute 6 back into the expression:

θ=6×360°×7144

Divide 144 by 6:

1446=24

This simplifies our expression to:

θ=360°×724

Now divide 360° by 24:

360°24=15°

Finally, multiply 15° by 7:

θ=15°×7=105°

Thus, the central angle of the sector is 105°.

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