3 Dimensional shapes

Three dimensional ( 3-D) shapes are also called solid shapes. They have length, breadth and height unlike 2-D shapes that have only length and breadth. Examples of 3-D shapes are cubes, cuboids, cylinders, prisms, pyramids and spheres. They are also called geometrical solids.

Key words

Face: a surface of solid shape

Edge: a line on a solid where two faces meet

Vertex (plural vertices): a point or corner on a solid, usually where edges meet

Net: a flat shape that you can fold to make a solid

General Evaluation/Revision Questions

1. A rectangular prism ( cuboid) has a volume of 680cm³ and its height is 20cm. What is the area of the base of the prism?
2. The base of a swimming pool is 192m². The depth of the swimming pool is 1.8m. find the volume of water the swimming pool can hold.
3. A book measures 18cm by 12cm by 3cm. Calculate its volume

Reading Assignment

• Essential Mathematics for J.S.S 1 by A. J. S Oluwasanmi, page 212-222.

Weekend Assignment

1. What is the volume of a cube of edge 5cm. (a) 15cm³  (b) 75cm³   (c) 125cm³   (d)  25cm³
2. Find the volume of air in a container whose dimensions are: length = 25cm, width = 20cm and height= 10cm (a) 5000cm³  (b) 2500cm³ (c) 4500cm³   (d) 500cm³
3. The volume of a cube is given as 512cm³. What is the length of one edge of the cube?  (a) 10cm  (b) 6cm   (c)  4cm  (d) 8cm
4. How many small cubes of edge 2cm can be placed together to make the cube in question 3 above? (a) 66 (b) 32  (c) 64   (d) 128
5. Calculate the volume of a cuboid with dimension 18cm by 12cm by 8cm. (a)  1728cm³  (b)  512cm³  (c)  144cm³  (d)  1872cm³

Theory

1. The base of a cuboid has one side equal to 10cm, and the other side is 5cm longer. If the height of the cuboid is 7cm, find the volume of the cuboid.
2. A cuboid measures xcm by 3xcm by 5xcm
3. Work out the volume of the cuboid in terms of x
4. What is the volume of the cuboid if x = 10cm?