Advertisements
Advertisements
प्रश्न
पर्याय
\[14\pi\]
\[\frac{7}{\pi}\]
7\[\pi\]
\[\frac{14}{\pi}\]
Advertisements
उत्तर
Let r be the radius of the circle.
Circumference of the circle : Area of the circle = 2 : 7
\[\Rightarrow \frac{2\pi r}{\pi r^2} = \frac{2}{7}\]
\[ \Rightarrow \frac{1}{r} = \frac{1}{7}\]
\[ \Rightarrow r = 7\]
∴ Circumference of the circle = \[2\pi r = 2\pi \times 7 = 14\pi\]
APPEARS IN
संबंधित प्रश्न
In Figure, find the area of the shaded region [Use π = 3.14]
A race track is in the form of a ring whose inner circumference is 352 m, and the outer circumference is 396 m. Find the width of the track.
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.
In the given figure, the side of square is 28 cm and radius of each circle is half of the length of the side of the square where O and O' are centres of the circles. Find the area of shaded region.
A gardener wants to fence a circular garden of diameter 21 m. Find the length of the rope he needs to purchase, if he makes 2 rounds of fence. Also find the costs of the rope, if it cost ₹ 4 per meter. (Take `pi = 22/7`)
Find the area of a trapezium whose parallel sides are 11 m and 25 m long, and the nonparallel sides are 15 m and 13 m long.
The areas of two circles are in the ratio 4: 9. What is the ratio between their circumferences?
PQRS is a diameter of a circle of radius 6 cm. The lengths PQ, QR and RS are equal. Semicircles are drawn with PQ and QS as diameters, as shown in the given figure. If PS = 12 cm, find the perimeter and area of the shaded region. [Take π = 3.14.]
The circumferences of two circles are in the ratio 3 : 4. The ratio of their areas is ______.
A 7 m road surrounds a circular garden whose area is 5544 m2. Find the area of the road and the cost of tarring it at the rate of Rs.150 per sq m.
The perimeter of a square and the circumference of a circle are equal. If the length of each side of the square is 22 cm, find:
(i) perimeter of the square.
(ii) circumference of the circle.
(iii) radius of the circle.
The inner circumference of a circular track is 264 m and the width of the track is 7 m. Find:
(i) the radius of the inner track.
(ii) the radius of the outer circumference.
(iii) the length of the outer circumference.
(iv) the cost of fencing the outer circumference at the rate of ₹50 per m.
Complete the table below.
| Radius (r) | Diameter (d) | Circumference (c) |
| ...... | 28 cm | ...... |
Complete the table below.
| Radius (r) | Diameter (d) | Circumference (c) |
| ...... | ...... | 616 cm |
Find the area and perimeter of the following semicircles: Diameter = 5.6cm
The circumference of a circle exceeds its diameter by 450 cm. Find the area of the circle.
The area between the circumference of two concentric circles is 2464cm2. If the inner circle has a circumference of 132cm, calculate the radius of the outer circle.
The area of a semicircle of radius 4r is ______.
