Scale Models and Maps

							COURSE 3 LESSON 5-7

                               Scale Models and Maps

                         On a blueprint, the living room is 4 in. by 3 in. The scale is
                1 in. = 8 ft. What are the length and width of the actual living room?
                2

          First, find the actual length of the living room.


          Let     = the actual length of the living room.


                                      1
          blueprint measure (in.)     2   4         blueprint length (in.)
            actual measure (ft)
                                        =             actual length (ft)
                                      8




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COURSE 3 LESSON 5-7


                                 Scale Models and Maps
                            (continued)

          1
            •         =8•4           Write the cross
          2
                                     products.
             1                       Simplify.
                  = 32
             2
             1
             2         32            Divide each side
                  =
             1         1                 1
                                     by .
             2         2                  2


                  = 64               Simplify.




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COURSE 3 LESSON 5-7

                              Scale Models and Maps

                        (continued)


          The length of the actual room is 64 ft.
          Next, find the actual width of the living room.
          Let w = the actual width of the living room.
                                      1
          blueprint measure (in.)     2   3         blueprint length (in.)
            actual measure (ft)
                                        =             actual length (ft)
                                      8   w




                                              5-7
COURSE 3 LESSON 5-7

                            Scale Models and Maps

                       (continued)


          1
            • w=8•3              Write the cross
          2
                                 products.

          1                      Simplify.
            w = 24
          2
          1w
          2    24                Divide each side
             =
          1    1                     1
                                 by .
          2    2                     2

            w = 48               Simplify.

          The width of the actual room is 48 ft.


                                             5-7
COURSE 3 LESSON 5-7
                             Scale Models and Maps

                         The map distance from El Paso, Texas, to Chihuahua,
               Mexico, measures about 7.5 cm. The scale is 1 cm = 50 km. Find the
               actual distance using a proportion.

          Let x = the actual distance.
               map (cm)           1   7.5          map (cm)
          actual measure (km)
                                     = x          actual (km)
                                  50

          1 • x = 50 • 7.5      Write the cross products.

              x = 375           Simplify.

          The distance from El Paso to Chihuahua is 375 km.




                                            5-7
COURSE 3 LESSON 5-7

                            Scale Models and Maps

          1. A 6-ft man is designing a new chair that would make him feel like a 2.5-ft
             child. The seat of a normal chair is 1.5 ft high. How high should he make
             the seat in his new chair?
              3.6 ft

          2. A map scale shows 4 cm to represent 6 km. Two intersections measure
             1 cm apart on the map. What is the actual distance?
              1.5 km




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