Similar figures, step by step
Two shapes are similar when one is a scaled copy of the other: same angles, sides all multiplied by the same number.
The question
cm
Similar figures: 8 and 16
small 8→large 16
16÷8=2
6×2=12
12 cm
- Two shapes, the same shape at two sizes. Every side of the big one is the matching side of the small one multiplied by the SAME number — so the first job is to pair the sides up: long with long, short with short.
- Use the pair you can see both of. 8 became 16, and 16 ÷ 8 = 2 — so every side is 2 times bigger.
- Now the missing side is on the BIG shape, so it grows: 6 × 2 = 12.
- Check it against the picture: the answer should be bigger than 6, and 12 is. So the missing side is 12 cm.
How it works.
- 01
Two shapes, the same shape at two sizes. Every side of the big one is the matching side of the small one multiplied by the SAME number — so the first job is to pair the sides up: long with long, short with short.
- 02
Use the pair you can see both of. 8 became 16, and 16 ÷ 8 = 2 — so every side is 2 times bigger.
- 03
Now the missing side is on the BIG shape, so it grows: 6 × 2 = 12.
- 04
Check it against the picture: the answer should be bigger than 6, and 12 is. So the missing side is 12 cm.