1. 11.3 – Perimeter and Area of Similar Figures

2. Find the ratio of the sides, perimeters, and areas of the similar rectangles.2 3 6 9 3 2
Ratio of Sides:

3. Find the ratio of the sides, perimeters, and areas of the similar rectangles.2 3 6 9
P =
P =
P =
24u
P =
16u 24 16 3 2
Ratio of Perimeters: =

4. 2 3 6 9 A = bh A = bh A = (9)(3) A = (6)(2) A = 27u2 A = 12u2 27 12 9
Find the ratio of the sides, perimeters, and areas of the similar rectangles. 2 3 6 9
A = bh
A = bh
A = (9)(3)
A = (6)(2)
A = 27u2
A = 12u2 27 12 9 4
Ratio of Areas: =

5. If two polygons are _____________ with the lengths of corresponding sides in the ratio ___________, then the ratio of their areas is ____________.
similar
a:b
a2:b2
S P A2 a2 b2 a b a b

6. 1. The ratio of the areas of two similar figures is given
1. The ratio of the areas of two similar figures is given. Write the ratio of the lengths of corresponding sides.
Ratio of areas = 4:225
S P A2
2 . 15
2 . 15
4 .
225

7. 1. The ratio of the areas of two similar figures is given
1. The ratio of the areas of two similar figures is given. Write the ratio of the lengths of corresponding sides.
Ratio of areas = 16:49
S P A2 4 7 4 7
16. 49

8. 1. The ratio of the areas of two similar figures is given
1. The ratio of the areas of two similar figures is given. Write the ratio of the lengths of corresponding sides.
Ratio of areas = 36:4
S P A2 3 1 3 1
36. 4 9 1 =

9. 2. Given the ratio of the sides of two similar figures, find the ratio of their perimeters and areas.
Ratio of sides = 1:3
S P A2 1 3 1 3
12. 32 1 9 =

10. 2. Given the ratio of the sides of two similar figures, find the ratio of their perimeters and areas.
Ratio of sides = 2:9
S P A2 4 81 2 9 2 9

11. 2. Given the ratio of the sides of two similar figures, find the ratio of their perimeters and areas.
Ratio of sides = 4:5
S P A2 16 25 4 5 4 5

12. 3. Use the given area to find XY.
S P A2
144 36 2 1 2 1 4 1 =
2x = 10
x =
5in

13. 3. Use the given area to find XY.
S P A2 2 3 2 3
168
378 4 9 =
2x = 24
x =
12cm

14. 4. Corresponding lengths in similar figures are given
4. Corresponding lengths in similar figures are given. Find the ratios (shaded to unshaded) of the perimeters and areas. Find the unknown area.
S P A2
1 . 16 2 8 1 4 1 4 =
x =
48ft2

15. 4. Corresponding lengths in similar figures are given
4. Corresponding lengths in similar figures are given. Find the ratios (shaded to unshaded) of the perimeters and areas. Find the unknown area.
S P A2
9 . 25 9 15 3 5 3 5 =
25x =
2025
x =
81in2

16. HW Problems #28 B 11.3 740-742 5-15 odd, 26-28, 35 S P A2 60 90 2 3 24. 9 =
9x = 80
x =
8.88 B