SURFACE AREAS
AND VOLUMES
Q. A toy is combination of a cylinder, hemisphere and a cone,
each with radius 10 cm. Height of the conical part is 10 cm and total
height is 60 cm. Find the total surface area and volume of the toy.
× 10
Volume of toy
= Volume of cone
+ Volume of cylinder
+ Volume of hemisphere
10 cm
10 cm
10 cm
Volume of toy =
3.14 ×
10 × 10
l = 14.1cm
1
3
πr2h
=
+
πr2H
+
2
3
πr3
=
πr2
× h +
1
3
H +
2
3
× r
=
1
3
+ 40
+
2
3
× 10
What is formula for finding volume of hemisphere ?
What is formula for finding volume of cylinder ?
40 cm
10 cm
What is formula for finding volume of cone ?
Volume of cone +
Volume of hemisphere
Volume of cylinder +
π r2 H
Sol.
60 cm
×
✔
✔
✔
✔
✔
Volume of toy =
Volume of cone +
Volume of hemisphere
Volume of cylinder +
10 cm
10 cm
10 cm
60 cm
10 cm
40 cm
Sol.
Volume of toy is 15700 cm3
∴
314
=
314
=
15700 cm3
=
3.14 ×
10 × 10
=
10
3
+ 40
+
20
3
30
3
+ 40
10
× 10
3.14 ×
10 × 10
=
1
3
+ 40
+
2
3
× 10
×
Q. A toy is combination of a cylinder, hemisphere and a cone,
each with radius 10 cm. Height of the conical part is 10 cm and total
height is 60 cm. Find the total surface area and volume of the toy.
×
×
314 × (10 + 40)
=
× 50