AI Mentor

Check Your IQ

Free Expert Demo

Try Test

Courses

Dropper NEET Course Dropper JEE Course Class - 12 NEET Course Class - 12 JEE Course Class - 11 NEET Course Class - 11 JEE Course Class - 10 Foundation NEET Course Class - 10 Foundation JEE Course Class - 10 CBSE Course Class - 9 Foundation NEET Course Class - 9 Foundation JEE Course Class -9 CBSE Course Class - 8 CBSE Course Class - 7 CBSE Course Class - 6 CBSE Course

Offline Centres

In the given figure, two concentric circles with center O have radii 21cm and 42cm , If ∠AOB=60∘ , find the area of the shaded region.

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

3652 cm2

3456 cm2

3564 cm2

3256 cm2

answer is B.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

As the angle of the minor sector for both the bigger and smaller circles is = 60∘.
So, the angle of the major sector for both the bigger and smaller circles = 300∘.
The formula for the area of the sector of circle is equal to

\frac{θ}{360} π r^{2}

The radius of the bigger circle = 42cm
The area of the major sector of bigger circle is:
A=

\frac{θ}{360} π r^{2}

= \frac{300}{360} \times 3.14 \times {(42 cm)}^{2}

= \frac{5}{6} \times 3.14 \times 1764

= 4620 c m^{2}

The radius of the smaller circle = 21cm
angle for the major sector of this circle= 300∘ .
The area of the major sector of smaller circle is:
A=

\frac{θ}{360} π r^{2}

= \frac{300}{360} \times 3.14 \times {(21 cm)}^{2}

= \frac{5}{6} \times 3.14 \times 441

= 1155 c m^{2}

So, the area of the shaded region is equal to

4620 c m^{2} - 1155 c m^{2} = 3465 c m^{2}

.
Therefore, the area of the shaded region is equal to 3465cm2.
So, the correct answer is “ 3465cm2”.

Watch 3-min video & get full concept clarity

courses

No courses found

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Online Course for IIT JEE

Best Online Course for NEET

Best Online Course for CBSE

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Get Expert Academic Guidance – Connect with a Counselor Today!