Advertisements
Advertisements
प्रश्न
Assertion (A)
The curved surface area of a cone of base radius 3 cm and height 4 cm is 15π cm2.\
Reason (R)
Volume of a cone = πr2h
- Both Assertion (A) and Reason (R) are true and Reason (R) is a correct explanation of Assertion (A).
- Both Assertion (A) and Reason (R) are true but Reason (R) is not a correct explanation of Assertion (A).
- Assertion (A) is true and Reason (R) is false.
- Assertion (A) is false and Reason (R) is true.
उत्तर
Assertion (A) is true and Reason (R) is false.
Assertion (A):
Curved surface area of a cone `=pisqrt("r"^2 + "h"^2 )`
`= pixx3xxsqrt((3)^2 + (4)^2)`
`=pixx3xxsqrt(9+16)`
`=pixx3xxsqrt(25)`
= 15 π cm2
Hene, Assertion (A) is true.
Reason (R): The given statement is false.
APPEARS IN
संबंधित प्रश्न
A bucket is in the form of a frustum of a cone with a capacity of 12308.8 cm3 of water.The radii of the top and bottom circular ends are 20 cm and 12 cm respectively. Find the height of the bucket and the area of the metal sheet used in its making. (Use 𝜋 = 3.14).
Find the volume of a cone if the radius of its base is 1.5 cm and its perpendicular height is 5 cm.
A well with 10 m inside diameter is dug 8.4 m deep. Earth taken out of it is spread all around it to a width of 7.5 m to form an embankment. Find the height of the embankment.
A right angled triangle with sides 3 cm and 4 cm is revolved around its hypotenuse. Find the volume of the double cone thus generated.
A solid is composed of a cylinder with hemispherical ends. If the whole length of the solid is 98 cm and the diameter of each of its hemispherical ends is 28 cm, find the cost of polishing the surface of the solid at the rate of 15 paise per sq cm.
The volumes of two cubes are in the ratio 8 : 27. Find the ratio of their surface areas.
If the surface area of a sphere is 616 cm2, its diameter (in cm) is ______. (Taking π = `22/7`)
If each edge of a cube is increased by 50%, the percentage increase in the surface area is
The total surface area of a hemisphere of radius 7 cm is
A farmer connects a pipe of internal diameter 20 cm from a canal into a cylindrical tank which is 10 m in diameter and 2 m deep. If the water flows through the pipe at the rate of 4 km/hr, then in how much time will the tank be filled completely?
