**Unit 12 **

**Dimensions **

1)

seale 1 : 100

This rectangular solid has a length of 5m

It is 5m long

It has width of 3.5m

It is 3.5m wide

It has a height of 1m

It is 1m high

It has a surface area of 52m2 (square metres). (A = 2 hw + 2 hl + 2lw )

It has a volume of 17.5m2 (cubic metres). ( V = 1 hw )

2)

Scale 1 : 10

This cylinder has a length of 65 cm

It is 65 cm long

It has a radius of 10 cm

It has a diameter of 20 cm

It has a surface area of 4714 square centimeters. ( A = **r2 + 2 **r2)

It has a volume of 20428 cubic centumetres ( V = **r2h )

3)

5m

6m

10m scale 1: 200

This water tank has a length of 10m

It is 10m long

It has a width of 5m

It is 5m wide

It has a height of 6m

It is 6m high

It has a capacity of 300 cubic metres

or 300.000 litres

or 3.000 hectolitres

4)

oil rig earth surface

Scale 1 : 3000 This oil rig has drilled to a depth of 150 metres

5)

2 cm

10 cm

This tube has an external diameter of 2 cm

It has an internal diameter of 1 – 5cm

It has a bore of 1 – 5 cm

The wall of the tube is 0 – 25 cm thick

It has a thickness of 0,25cm

It has a surface area of 112.75cm2

( A = **d

it has a capacity of 17.68cm3 ( C = **r2h )

1 mm

6)

This glass tube has a bore of 1mm

It has a fine or narrow bore

It has a capacity of 23.6mm3

3 cm

## Practice 1

Describe the following figures. The measurements are given

1) 2)

3 cm

4 cm

3)

5 cm 3 cm

4 cm

4)

3 cm

2 cm

2,5 cm

5)

4 cm

6) 7)

1,5cm

3 cm

## Practice 2

Use your ruler

1) EartnsSarface

air

Water

Scale 1 : 1000

Above is a diagram of a cylindrical well

Describe the well

2)

Front of view (elevation)

scale 1 : 100 Top view

above are the elevation and plan of a water tank

3)

Sice view

Scale 1:5

Front view

Above are the side view and frontal view of tube

Describe the tube

## Practice 3

1. A. table a length of 1 meter and width of 80cm. The top of the table is 4cm thick.

Te overall height of the table is 64 cm. The legs of the table measure 60 x 5 x 5.

draw a side view of the table on the scale 1 :20

2. A clock has a circular face with a diameter of 20cm. The minute hand is 8cm long

and the hour hand is 5cm long. The case of the clock is rectangular with a length

of 30cm and a height of 25cm. Draw a frontal view of the clock on the scale 1:2

with the clock showing the time at 10 minutes past 10.

3. A country national flag is 180cm wide and 100cm deep. It consists of three equal

vertical stripes, blue, green and black from left to right. In the central position

there is a white disc with a diameter of 50cm. Draw a picture of this flag on the