1. To understands what scale drawings are. To be able to draw scale drawings

2. What are scale drawings? Scale drawings are everywhere! Scale Drawings On Maps Footprints of houses Vehicle design Can you think of any more?

3. Scale drawings are SIMILAR to the original. Same shape, different size. Similar - same angles and the sides must be in the same ratio. Example: Are these two shapes similar? Angles the same x2 Sides have the same ratio – x2 The two shapes are similar

4. Are these pairs of shapes similar ? 3cm 9cm 2cm 6cm 40° 50° 5m 6m 4m 10m 2m 3m 1m 1.5m 50° 60° 70°

5. All scale drawings must have a scale written on them. Scales are usually expressed as ratios. Normally for drawings and building plans the ratio: Drawing length: Actual length For maps the ratio is normally in the ratio: Map distance: Actual Distance Example: 1cm : 100cm The ratio 1cm:100cm means that for every 1cm on the scale drawing the length will be 100cm in real life Example: 1:10000 The ratio 1:10000 means that the real distance is 10000 times the length of one unit on the map or drawing.

6. When you write a scale you must make sure that the units are the same. Example Simplify the scale 5cm to 1m 5cm:1m 5cm:100cm 1cm:20cm Convert to the same units Simplify Questions – Simplify the following scales 1) 10cm: 2m 2) 5mm:10cm 3) 1cm:1km 1cm:20cm 1mm:20mm 1cm:100000cm