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Auralith Learning

Year 8 · Maths · Ratio and scale · Lesson 3

Scale drawings and maps

Learn to use scales on drawings, plans, models and maps, convert between centimetres, metres and kilometres, and write a scale as a ratio.

Whiteboard video lesson: Scale drawings and maps

30-minute video lesson

Teaching, worked examples and 20 practice questions solved step by step.

Watch free for a month

What your child will learn

  • Use a scale to find a real length from a drawing
  • Use a scale to find a length on a drawing
  • Use map scales such as 1 : 25,000
  • Convert between cm, m and km
  • Write a scale as a ratio 1 : n

The method

  1. Drawing to real life: multiply.
  2. Real life to drawing: divide.
  3. Change units carefully between cm, m and km.
  4. A ratio scale like 1 : 50,000 means 1 cm = 50,000 cm.

Key words: scale, scale drawing, map scale, ratio, units of length.

Worked examples

The first three practice questions from the lesson, with every step.

Question 1

A drawing has a scale of 1 cm : 3 m. A line on the drawing is 4 cm long. How long is it in real life?

  1. Step 1: Drawing to real: multiply
  2. Step 2: 4 × 3 = 12 m

Answer: 12 m

Question 2

The scale is 1 cm : 5 m. A wall is 7 cm long on the plan. How long is the real wall?

  1. Step 1: Drawing to real: multiply
  2. Step 2: 7 × 5 = 35 m

Answer: 35 m

Question 3

A map has a scale of 1 cm : 2 km. Two villages are 6.5 cm apart on the map. How far apart are they in real life?

  1. Step 1: Drawing to real: multiply
  2. Step 2: 6.5 × 2 = 13 km

Answer: 13 km