All in One Mathematics>Chapter 11 - Surface Areas and Volumes>Exam Practice>Q 25

HARD

9th CBSE

IMPORTANT

Earn 100

$27$ solid iron spheres, each of radius $2 cm$ are melted to form a new solid sphere. What will be the surface area of the new sphere?

Important Questions on Surface Areas and Volumes

HARD

9th CBSE

IMPORTANT

All in One Mathematics>Chapter 11 - Surface Areas and Volumes>Exam Practice>Q 27

The radius of a sphere is

5 c m

. If the radius be increased by

20 %

, find how much percent the volume is increased?

EASY

9th CBSE

IMPORTANT

All in One Mathematics>Chapter 11 - Surface Areas and Volumes>Exam Practice>Q 28

If the radius of a sphere is doubled, then find the percentage increase in its volume.

MEDIUM

9th CBSE

IMPORTANT

All in One Mathematics>Chapter 11 - Surface Areas and Volumes>Exam Practice>Q 29

Find the area of the metal sheet required to make two close hollow cones each of height

24 c m

and slant height

25 c m .

MEDIUM

9th CBSE

IMPORTANT

All in One Mathematics>Chapter 11 - Surface Areas and Volumes>Exam Practice>Q 30

To maintain beauty of a monument, the students of the Delhi Public School cleaned and painted the dome of the monument. The monument is in the form of a hemisphare. From inside, it was white washed by the students, whose area is

997.92 m^{2}

, then find the volume of the air inside the dome. If white washing costs

₹ 2 per m^{2}

, how much does it costs?

MEDIUM

9th CBSE

IMPORTANT

All in One Mathematics>Chapter 11 - Surface Areas and Volumes>Exam Practice>Q 31

Shashi has a piece of canvas whose area is

1102 m^{2}

. She uses it to make a conical tent with base radius

14 m

. Wastage in stitching margin and cutting amounts is

2 m^{2}

. Find the volume of the tent that can be made with it. (take,

\sqrt{429} = 20.71

)

HARD

9th CBSE

IMPORTANT

All in One Mathematics>Chapter 11 - Surface Areas and Volumes>Exam Practice>Q 33

Two hemispherical domes are to be painted as shown in the given figure. If the circumferences of the bases of the domes are $17.6 cm$ and $70.4 cm$ respectively, then find the cost of painting at the rate of $₹ 10$ per ${cm}^{2}$ .

Question Image

EASY

9th CBSE

IMPORTANT

All in One Mathematics>Chapter 11 - Surface Areas and Volumes>Exam Practice>Q 34

The volume of two spheres are in the ratio

64 : 27

. Find their radii if the sum of their radii is

21 cm

.

EASY

9th CBSE

IMPORTANT

All in One Mathematics>Chapter 11 - Surface Areas and Volumes>Exam Practice>Q 35

If the height of a cone is doubled, then find the percentage increase in its volume.