11'3 Perimeters

1
11.3 Perimeters Areas of Figures

• p. 677

2
Thm 11.5 Areas of Polygons

• If 2 polygons are with a ratio of corresponding
  sides ab, then the ratio of their areas is
  a2b2.
• ratio of perimeters
• scale factor or
• ratio of areas

b
a
2
1
Polygon 1 Polygon 2
3
Ex The ratio of corresponding sides of 2
hexagons is 32.

• (a.) Find the ratio of their perimeters.
• 32
• (b.) Find the ratio of their areas.
• 94
• (c.) If the area of the larger hexagon is 45 in2,
  what is the area of the smaller hexagon?
• 9x 180
• x 20 in2

4
Ex A rectangular tablecloth is 60 in X 120 in.
A rectangular placemat made from the same cloth
is 12 in X 24 in costs 5. Compare the areas
of these objects to find a reasonable cost for
the tablecloth.

• First, are the rectangles ?
• Yes
• Placemat Tablecloth
• Area
• 288 in2 7200 in2
• Cost 5
• 5 25 125

5
Ex A store sells trampolines that are all
regular hexagons. One trampoline has a side
length of 4.5 ft and an area of 52.6 ft2. Find
the area of a trampoline whose perimeter is 67.5
ft.
4.5 ft
11.25 ft
A 52.6 ft2
P 67.5 ft
Set up a proportion using the ratio of the areas
the ratio of the actual areas.
x 328.75 ft2
6
Assignment