1. Side Ratio Perimeter Ratio Area Ratio 1:5 1:5 1:25 4:3 4:3 16:9 3:1
Find the area and perimeter of a rectangle with dimensions:
4 by 10 28 40
8 by 20 56
160
6 by 15 42 60
20 by 50
140
1000
2 by 5 14 10
Side Ratio Perimeter Ratio Area Ratio
1:5
1:5
1:25
4:3
4:3
16:9
3:1
3:1
9:1

2. Side Ratio Perimeter Ratio Area Ratio 1:5 1:5 1:25 4:3 4:3 16:9 3:1
Do you notice a relationship between the side ratio, perimeter ratio, and area ratio?
Theorem 7-11
If the scale factor of two similar figures is a:b, then:
1) The ratio of perimeters is a:b
2) The ratio of areas is a2:b2
Find the area and perimeter of a rectangle with dimensions:
4 by 10 28 40
8 by 20 56
160
6 by 15 42 60
20 by 50
140
1000
2 by 5 14 10
Side Ratio Perimeter Ratio Area Ratio
1:5
1:5
1:25
4:3
4:3
16:9
3:1
3:1
9:1

3. Any ideas why the ratio is squared?
Something useful from the book:
1) If two triangles have equal heights, then the ratio of the areas is equal to the ratio of the bases.
2) If two triangles have equal bases, then the ratio of their areas equals the ratio of their heights
3) If two triangles are similar, then the ratio of their areas equals the square of their scale factor.
Any ideas why the ratio is squared? 4 8 8 4 6 12 6 24 40 9 36 18 2 6 10 3 6 6
Height same, Base ratio 3:5, area ratio 3:5
Base same, Height ratio 2:1, area ratio 2:1

4. Two basic problems:
I have two pentagons. If the area of one pentagon is 100, and they have a 1:4 side length ratio, then what is the area of the other pentagon?
I have 2 dodecagons. If the area of one is 314 and the other is 942, what is the side length ratio?

5. 24) Find the ratio between:
1) red, orange
2) red, green
3) red, blue
4) green, blue
5) red, trap 13 5
1:4
1:2
1:1
1:9 12 5 10
Key is to look at side length ratios. use pen to write, next click will have answers

6. R - HW #36:  Pg 458: 2—12 even, 13, 14, 17—20, 22, 24, 26—29
Remember, test Wednesday