Advertisements
Advertisements
प्रश्न
The area of a circle is 38.5 cm2. The circumference of the circle is
विकल्प
6.2 cm
12.1 cm
11 cm
22 cm
उत्तर
22 cm
Let the radius be r cm.
We know:
Area of a circle
= πr2 cm2
Thus, we have
πr2 = 38.5
`=>22/7xx"r"^2 = 38.5`
`⇒ r^2 = (38.5xx7/22)`
`=> "r"^2 = (385/10xx7/22)`
`=> "r"^2 = 49/4`
`=> r = 7/2`
Now,
Circumference of the circle = 2πr
`= 2 × 22/7xx"r"`
`=(2xx22/7xx7/2)`
= 22 cm
APPEARS IN
संबंधित प्रश्न
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)
A horse is placed for grazing inside a rectangular field 40m by 36m and is tethered to one corner by a rope 14m long. Over how much area can it graze.
The shape of the cross section of a canal is a trapezium. If the canal is 10 m wide at the top, 6 m wide at the bottom and the area of its cross section is `640m^2` , find the depth of the canal.
The sum of the radii of two circles is 7 cm, and the difference of their circumferences is 8 cm. Find the circumference of the circles.
A horse is placed for grazing inside a rectangular field 70 m by 52 m. It is tethered to one corner by a rope 21 m long. On how much area can it graze? How much area is left ungrazed?
If the sum of the circumferences of two circles with radii R1 and R2 is equal to the circumference of a circle of radius R, then ______.
A 4.2 m wide road surrounds a circular plot whose circumference is 176 m. Find the cost of paving the road at Rs 75 m 2.
Each side of a square is 44 cm. Find its perimeter. If this perimeter is equal to the circumference of a circle, find the radius of the circle.
The area of a quadrant of a circle whose circumference is 22 cm, is ____________.
The area of a circular playground is 22176 m2. Find the cost of fencing this ground at the rate of Rs 50 per metre.
