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Think About a Plan Two similar rectangles have areas
27
in
.
2
27 in , . squared and
48
in
.
2
.
48 in , . squared , . The length of one side of the larger rectangle is 16 in. What are the dimensions of both rectangles?
- How does the ratio of the similar rectangles compare to their scale factor?
- How can you use the dimensions of the larger rectangle to find the dimensions of the smaller rectangle?
- The longer sides of a parallelogram are 5 m. The longer sides of a similar parallelogram are 15 m. The area of the smaller parallelogram is
28
m
2
.
28 , m squared , . What is the area of the larger parallelogram?
Algebra Find the values of x and y when the smaller triangle shown here has the given area.
-
3
cm
2
3 , cm squared
-
6
cm
2
6 , cm squared
-
12
cm
2
12 , cm squared
-
16
cm
2
16 , cm squared
-
24
cm
2
24 , cm squared
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48
cm
2
48 , cm squared
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Medicine For some medical imaging, the scale of the image is 3 : 1. That means that if an image is 3 cm long, the corresponding length on the person's body is 1 cm. Find the actual area of a lesion if its image has area
2
.
7
cm
2
.
2 . 7 , cm squared , .
- In
Δ
R
S
T
,
R
S
=
20
m
,
S
T
=
25
m
,
cap delta r s t comma r s . equals 20 m comma s t equals 25 m comma and
R
T
=
40
m
.
r t equals 40 m .
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Open-Ended Choose a convenient scale. Then use a ruler and compass to draw
Δ
R
′
S
′
T
′
∼
Δ
R
S
T
.
cap delta r , prime s . prime t prime tilde operator . cap delta r s t .
-
Constructions Construct an altitude of
Δ
R
′
S
′
T
′
cap delta r , prime s . prime t prime and measure its length. Find the area of
Δ
R
′
S
′
T
′
.
cap delta r , prime s . prime t prime .
-
Estimation Estimate the area of
Δ
R
S
T
.
cap delta r s t .
Compare the blue figure to the red figure. Find the ratios of (a) their perimeters and (b) their areas.
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-
-
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- Find the area of a regular hexagon with sides 2 cm long. Leave your answer in simplest radical form.
- Use your answer to part (a) and Theorem 10-7 to find the areas of the regular hexagons shown below.
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Writing The enrollment at an elementary school is going to increase from 200 students to 395 students. A parents' group is planning to increase the 100 ft-by-200 ft playground area to a larger area that is 200 ft by 400 ft. What would you tell the parents' group when they ask your opinion about whether the new playground will be large enough?