Vocabulary
What does it mean if two figures are similar?
Same shape, proportional sides, equal angles.
The side of a small triangle is 4 cm, and the corresponding side of a larger triangle is 12 cm. What is the scale factor?
1:3
A map uses the scale 1 in = 10 miles. If two towns are 3 in apart on the map, how far apart are they actually?
30 miles
A model car is built at a scale of 1in:10ft. The actual car is 15 ft long. How long is the model?
1.5in
A photograph is 4 in by 6 in. Enlarged by a scale factor of 2, what is the new size?
8 in × 12 in
Define scale factor
Ratio comparing drawing to actual size
A rectangle in a scale drawing is 5 cm wide. The actual rectangle is 20 m wide. What is the scale factor?
1:4
On a blueprint, a wall measures 8 cm. The actual wall is 16 m. What is the scale factor?
1:2
A room measures 4 in by 6 in on a blueprint with a scale of 1 in = 3 ft. Find the actual area of the room.
(4×3) × (6×3) = 12 ft × 18 ft = 216 ft²
A map has a scale of 1 cm = 100 m. Two parks are 5 cm apart on the map. What’s the actual distance?
500 m
What are corresponding sides? Give an example
Matching sides
If a figure is enlarged by a scale factor of 3, what happens to the perimeter?
Perimeter ×3
A 2 in by 4 in rectangle is drawn with a scale factor of 3. What are the new dimensions?
6 in × 12 in
A garden is 7 cm by 10 cm on a drawing. The scale is 1 cm = 2 m. Find the actual perimeter.
14 m × 20 m → P = 68 m.
A mural is drawn at 8 in × 10 in. The scale factor is 15. What will be the actual dimensions?
120 in × 150 in
True or False: A reduction makes a figure smaller, but the shape stays the same.
True
If a scale drawing has a factor of 1:5, what does that mean?
1 drawing unit = 5 actual units.
A 6 cm by 10 cm rectangle is reduced by a scale factor of ½. What are the new dimensions?
3 cm × 5 cm
A rectangle is enlarged with a scale factor of 2. If the original area was 12 cm², what is the new area?
12 × 2² = 48 cm².
A floor plan shows a swimming pool as 3 in × 5 in, with a scale of 1 in = 4 ft. What is the actual size of the pool?
12 ft × 20 ft
Explain the difference between a scale drawing and the actual figure.
Drawing = representation; actual = real object.
Two similar figures have areas of 25 cm² and 100 cm². What is the scale factor of their side lengths?
2
A triangle on a map has sides of 2 cm, 3 cm, and 4 cm. If the scale is 1 cm = 5 ft, what are the actual side lengths?
10 ft, 15 ft, 20 ft
You just broke your mom Princess house set and she launched a whole chancla measuring at 12in by 3in so fast it stretch on the way to impact to you at a scale factor of 3? What size was the chancla before it knock you out?
36in by 9in and a bruce.
A scale model of a building has a height of 12 in. The actual building is 144 ft tall. What is the scale factor?
1:12