Grade 7 Proportions: Scale Drawings

Worked examples

Real problems from the practice worksheets, solved one step at a time.

1. Example 1

   A map has a scale of 1:3. A road is 20 cm long on the map. How long is the real road, in cm?

   1. A scale of 1:3 means 1 cm on the map stands for 3 cm in real life.
   2. Multiply the map length by 3: 20 × 3 = 60.
   3. So the real road is 60 cm long.

   Answer: 60

2. Example 2

   A map has a scale of 1:4. A road is 37 cm long on the map. How long is the real road, in cm?

   1. A scale of 1:4 means 1 cm on the map stands for 4 cm in real life.
   2. Multiply the map length by 4: 37 × 4 = 148.
   3. So the real road is 148 cm long.

   Answer: 148

3. Example 3

   A map has a scale of 1:4. A road is 54 cm long on the map. How long is the real road, in cm?

   1. A scale of 1:4 means 1 cm on the map stands for 4 cm in real life.
   2. Multiply the map length by 4: 54 × 4 = 216.
   3. So the real road is 216 cm long.

   Answer: 216