Advertisements
Advertisements
प्रश्न
Find the circumference of the circle whose area is 25 times the area of the circle with radius 7 cm.
उत्तर
Area of the circle with radius 7 cm = π r2
`= 22/7 xx 7 xx 7`
= 154 cm2
Area of new circle = 25 x area of the drde with radius 7 cm
= 25 x 154 cm2
= 3850 cm2
Therefore ,
π R2 = 3850
R2 = `3850 xx 7/22`
R2 = 1225
R = 35 cm
Radius of new circle = 35 cm
Circumference of new circle = 2 π R
`= 2 xx 22/7 xx 35`
= 220 cm
Hence, Circumference of new circle = 220 cm
APPEARS IN
संबंधित प्रश्न
All the vertices of a rhombus lie on a circle. Find the area of the rhombus, if the area of the circle is 1256 cm2. (Use π = 3.14)
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)
If the circumference of a circular sheet is 154 m, find its radius. Also find the area of
the sheet. (Take `pi = 22/7`)
The circumference of a circle exceeds diameter by 16.8 cm. Find the circumference of
circle.
Four equal circles each of radius a, touch each other. Show that area between them is `6/7a^2`
The wheels of the locomotive of a train are 2.1 m in radius. They make 75 revolutions in one minute.
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 ______.
The perimeter of a sector of a circle of radius 5.6 cm is 27.2 cm. Find the area of the sector.
Find the curved surface area , the total surface area and the volume of a cone if its :
Height = 12 cm , radius = 5 cm
A conical tent with a capacity of 600 m3 stands on a circular base of area 160 m2 Find in m2 the area of the canvas.
A canvas tent is in the shape of a cylinder surmounted by a conical roof. The common diameter of the cone and the cylinder is 14 m. The height of the cylindrical part is 8 m and the height of the conical roof is 4 m. Find the area of the canvas used to make the tent.
Find the area enclosed between two concentric cirdes of radii 6.3 cm and 8.4 cm. A third concentric circle is drawn outside the 8.4 cm circle, so that the area enclosed between it and 8.4 cm cirde is the same as that between two inner circles. Find the radii of the third circle correct to two decimal places .
The base circumferences of two cones are the same. If their slant heights are in the ratio 5 : 4, find the ratio of their curved surface areas.
Find the volume and the surface area of the spheres in the following :
Diameter= 6.3 cm
A wheel has a diameter of 84 cm. Find how many completer revolutions must it make to cover 3.168 km.
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.
Circumference of a circle disc is 88 cm. Its radius is ______.
The area of a square is 100 cm2. The circumference (in cm) of the largest circle cut of it is ______.
A circle with radius 16 cm is cut into four equal parts and rearranged to form another shape as shown in the below figure:
Does the perimeter change? If it does change, by how much does it increase or decrease?
Ishika has designed a small oval race track for her remote control car. Her design is shown in the given figure. What is the total distance around the track? Round your answer to the nearest whole centimetre.
