Page 92 - MAT KS3 Y8 Cambridge CheckPoint

8.4 Drawing nets of solids

8.4 Drawing nets of solids

A net shows the 2D layout of a 3D solid.
The net will fold up to make the solid.
To work out the net of a 3D object, imagine cutting it along its edges and unfolding it.
You need to be able to make a sketch of the net of a 3D solid. You also
A sketch is an approximate
need to be able to make an accurate drawing of the net of a 3D solid. In an
drawing – the lengths don’t
accurate drawing all the lengths must be exactly the correct measurements.
need to be accurate.
There are often different ways to draw the net of a 3D solid. For example,
here are three of the ways you could draw a net of the cube above.

Worked example 8.4
3 cm 3 cm
a Draw a sketch of the net of a square-based pyramid.
b Draw an accurate drawing of the net of this triangular prism.
2 cm
6 cm
4.5 cm

a A square-based pyramid looks like this.

To draw the net, start by drawing the square base, then draw an
isosceles triangle on each side of the square base.
Start by drawing the base of the triangular prism. This is a
b 3 cm c
2 cm
3 rectangle that must measure exactly 6 cm by 4.5 cm.
d Next draw the two sloping sides. These are both rectangles that
must measure exactly 6 cm by 3 cm.
2 1 2 6 cm
e Finally draw the two triangular ends of the prism. These are both
isosceles triangles. The easiest way to draw these is to measure
2 cm from the centre of the base rectangle, then join this point to
3 the corners of the base rectangle.

3 cm 4.5 cm 3 cm

✦ Exercise 8.4

1 Sketch a net of each cuboid.
a b

90 8 Shapes and geometric reasoning