Advertisements
Advertisements
Question
The circumference of a circle exceeds its diameter by 450 cm. Find the area of the circle.
Advertisements
Solution
Let the radius of a circle = r cm
⇒ Circumference of a circle = 2πr cm
Diameter of a circle = 2r cm
Now, Circumference of a circle - Diameter of a circle = 450m
⇒ 2πr - 2r = 450
⇒ 2r(π - 1) = 450
⇒ `2"r"(22/7 - 1)` = 450
⇒ `2"r" xx (15)/(7)` = 450
⇒ r = `(450 xx 7)/(2 xx 15)`
= 105cm
∴ Area of a circle
= πr2
= `(22)/(7) xx 105 xx 105`
= 34650cm2.
APPEARS IN
RELATED QUESTIONS
The length of minute hand of a clock is 14 cm. Find the area swept by the minute hand in one minute. (Use π = 22/7)
An arc of a circle is of length 5π cm and the sector it bounds has an area of 20 π cm2. Find the radius of the circle.
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.
The difference between the circumference and radius of a circle is 37cm. Using `pi = 22/7` , find the circumference of the circle.
Find the radius of a circle whose perimeter and area are numerically equal.
The length of a chain used as the boundary of a semicircular park is 108 m. Find the area of the park.
The area of an equilateral triangle is `49sqrt(3)` cm2 . Taking each angular point as centre, circles are drawn with radius equal to half the length of the side of the triangle. Find the area of the triangle not included in the circles. [Take π = 1.73]
Complete the table below.
| Radius (r) | Diameter (d) | Circumference (c) |
| ...... | 28 cm | ...... |
Diameters of different circles are given below. Find their circumference (Take π = `22/7`)
d = 28 mm
The diameters of front and rear wheels of a tractor are 80 cm and 2 m respectively. Find the number of revolutions that rear wheel will make in covering a distance in which the front wheel makes 1400 revolutions.
