The circumference of a circle exceeds its diameter by 30 cm. The area (in cm
2
) of the circle is: (Take π=
7
22
)
- A300
- B216
- C154
- D145
Solution & Step-by-step Explanation
Let the radius of the circle be r cm. Then its circumference is 2πr and its diameter is 2r.
According to the question:
2πr−2r=30
2r(π−1)=30
2r(
7
22
−1)=30
2r×
7
15
=30
7
30r
=30⟹r=7 cm
Now, find the area of the circle:
Area=πr
2
=
7
22
×7×7=22×7=154 cm
2
According to the question:
2πr−2r=30
2r(π−1)=30
2r(
7
22
−1)=30
2r×
7
15
=30
7
30r
=30⟹r=7 cm
Now, find the area of the circle:
Area=πr
2
=
7
22
×7×7=22×7=154 cm
2