9th Grade > Mathematics
SURFACE AREAS AND VOLUMES MCQs
:
C
1 litre = 1000 cm3
40 litres = 40000 cm3
Volume of water in the container
=40 litres = 40000 cm3
Volume of each ice cube
=(Side)3
=53
=125 cm3
∴ Number of ice cubes that can be fitted
=Volume of water containerVolume of each cube
=40000 cm3125 cm3
=320 ice cubes
:
B
Radius of the sphere
=diameter2=142=7 m
Area available to the motorcyclist = Surface area of the sphere
=4πr2
=4×227×72
=616 m2
Hence, the available area to the motorcyclist is 616 m2.
:
B
Given,
Total surface area of the cube =54 cm2
We know that,
Cube has 6 number of faces.
Each face of the Rubik's cube contains 9 tiles.
Each Rubik's cube contains 9 red tiles.
∴ Area of each face
=Total surface area of the cubeTotal number of faces of the cube=546=9 cm2
Now, area of each tile
=Area of each faceTotal number of tiles in each face=99=1 cm2
Hence, the area occupied by every single red tile of the cube is 1 cm2.
:
A
We know that,
volume of a cylinder =πr2h
Number of glasses of juice that are sold
=volume of the vesselvolume of each glass=π×10×10×35.2π×4×4×10=22
∴ The amount earned by the shopkeeper
=Rate of each glass×Total number of glasses
=10×22=₹ 220/−
:
C
We know that,
volume of cone =13πr2h
volume of hemisphere =23πr3
Total volume
= Volume of the cone + Volume of the hemisphere
=13πr2h+23πr3=13πr2(h+2r)=13×227×3.52×(5+7)=13×227×3.52×12=22×0.5×3.5×4=154 cm3
∴ The volume of the solid formed is
154 cm3
:
A and B
Cuboids can be formed by stacking rectangles as shown in the figure.
A square can be defined as a rectangle in which the adjacent sides are equal. Thus, stacking squares also yields cuboids. In fact, we obtain a special type of cuboid in this case, called the cube.
:
A
Curved surface area of the cylindrical pillar
=2πrh
=2×227×3.5×10
=220 m2
So,
total cost of painting
=Curved Surface Area of pillar×Cost per m2
=220×10
= ₹ 2200/-
Hence, the given statement is true.
:
B
Total surface area =3πr2
⇒3×227×r2=1848
⇒r2=1848×73×22
⇒r2=196
⇒r=14 cm
Thus, above statement is false.