Using the scale to convert a real-life measurement to what it should be on the drawing (e.g., 6 m at 1:100 = 6 cm).
Where your child meets this in real life: Drawing a plan of your bedroom to scale or creating a map of the school grounds
SEAGReady breaks calculate scale measurements into 2 steps, taught in order so each skill builds on the last.
Calculate the drawing measurement when the real-life measurement uses the same unit as the scale (e.g., 500 cm at 1:100 = 5 cm)
Calculate the drawing measurement when the real-life measurement is in different units (e.g., 6 m at 1:100 = 6 cm)
Three free sample questions from our calculate scale measurements course. Every question comes with a full explanation, and hints that guide without giving the answer away.
Sean is drawing a scale plan of his bedroom. The wall is 300 cm long. He uses a scale of 1:100. How long should the wall be on his drawing?
Answer: A. 3 cm
Scale 1:100 means 1 cm on drawing = 100 cm in real life. To find the drawing measurement, divide by the scale factor: 300 cm divided by 100 = 3 cm The wall should be 3 cm on the drawing.
Stuck? Start here: The scale is 1:100. This means 1 cm on the drawing represents 100 cm in real life.
Niamh is drawing a scale plan of the school playground. The playground is 6 metres wide. She uses a scale of 1:100. How wide should the playground be on her drawing?
Answer: A. 6 cm
Step 1: Convert metres to centimetres. 6 m = 6 x 100 = 600 cm Step 2: Divide by the scale factor. 600 cm divided by 100 = 6 cm The playground should be 6 cm wide on Niamh's drawing.
Stuck? Start here: The scale uses centimetres. What do you need to do first?
Aoife is making a scale drawing of the school hall. A wall measures 500 cm in real life. Using a scale of 1:100, how long is the wall on her drawing?
Answer: B. 5 cm
Scale 1:100 means 1 cm on drawing = 100 cm in real life. To find the drawing measurement, divide by the scale factor: 500 cm divided by 100 = 5 cm The wall should be 5 cm on the drawing.
Stuck? Start here: Look at the scale: 1:100. What operation do you need to go from real life to drawing?
This is the exact interactive worked example your child sees in SEAGReady. Step through it and watch the method build up.
Niamh is drawing a scale plan of her classroom for a school project. The classroom wall is 400 cm long. She uses a scale of 1:100.
How long should the wall be on her drawing?
400 cm ÷ 100
Step 1 of 4
Niamh is drawing a scale plan of her classroom for a school project. The classroom wall is 400 cm long. She uses a scale of 1:100.
How long should the wall be on her drawing?
The wall should be 4 cm long on Niamh's drawing.
The key insight: Real to drawing is the opposite of drawing to real - so we divide instead of multiply!
Watch out: 400 × 100 = 40,000 cm. Multiplying makes the drawing bigger than real life - we need to divide to shrink it.
These are the misconceptions we see most often in calculate scale measurements, including the ones our practice questions are specifically designed to catch.
Struggling with calculate scale measurements? The real gap is often in one of these earlier topics.
SEAGReady finds the exact step where your child gets stuck, teaches it with worked examples like the one above, and brings it back for review so it sticks.