Chapter Study Guide and Review
308 Proportions and SimilarityScale Drawings and Models
PSI: Draw a Diagram (Lesson 2A)
Solve each problem by drawing a diagram.- WATER A 500-gallon hot tub is being filled
with water. Eighty gallons of water are in
the hot tub after 4 minutes. At this rate,
how long will it take to fill the hot tub? - GEOMETRY A diagonal is a line segment
that connects two non adjacent vertices.
Find the number of diagonals in an
octagon.
EXAMPLE 4 Alvin has filled _^1
3 or
50 gallons of his fish tank. Find the total
capacity of the fish tank.of the fish tankof the fish tank 255075100125150
2
3
1
3If _ 31 of the fish tank is 50 gallons, then _^23 is
100 gallons. So, the total capacity of the fish
tank is 50 + 100, or 150 gallons.Scale Drawings (Lesson 2B)
The scale on a map is 3 centimeters =
7 kilometers. Find the actual distance for
each map distance.- 9 cm 26. 21 cm
- ARCHITECTS On an architect’s blueprint,
the dimensions of a room are 5 inches by
8 inches. If the actual dimensions of the
room are 10 feet by 16 feet, what is the
scale of the blueprint? - MODELS A Boeing 747 jet is 70.5 meters
long and has a wingspan of 60 meters.
A model of the 747 has a wingspan of
80 centimeters. What is the length of
the model?
60 m70.5 mEXAMPLE 5 On a map, the distance
between two cities is 10.9 centimeters. If
the scale is 1 centimeter = 250 kilometers,
what is the actual distance?
Scale Distance
map
actual^_1 cm
250 km
= _10.9 cm
n kmmap
actual
1 · n = 250 · 10.9
n = 2,725
The actual distance is 2,725 kilometers.EXAMPLE 6 The scale on a model of a
bullfrog is 2 centimeters = 25 millimeters.
Find the actual length of the bullfrog if
the model length is 11 centimeters.
_25 mm2 cm = _11 cmx mm model lengthactual length2 · x = 25 · 11 Find the cross products.
2 x = 275 Multiply.
x = 137.5 Divide each side by 2.
The actual length is 137.5 millimeters.Lesson 2306_310_C05_SGR_895130.indd 308 12/29/09 1:08 PM