7th Grade Math

Lesson 2A Scale Drawings and Models 283

= Step-by-Step Solutions begin on page R1.

Extra Practice begins on page EP2.

• Draw a diagram.


• Look for a pattern.


• Work backward.


• Choose an operation.

Use the draw a diagram strategy to solve

Exercises 2–5.

2. A string is cut into 3 pieces in the ratio of
   1 : 2 : 4. If the longest piece is 16 inches
   longer than the medium piece, find the
   length of the original string.

Piece 3

Piece 2

Piece 1

16 in.

3. TILES A kitchen is 10 feet long and 8 feet
   wide. If kitchen floor tiles are 2 _^12 inches by
   3 inches, how many tiles are needed for
   the kitchen?


4. TRAVEL There are four seats in Clarence’s
   car: two in the front and two in the back. If
   Benny, Carlita, and Juanita are all in the car
   with Clarence, how many ways can they
   be seated in the car if Clarence is driving?
   55 GARDENING Mr. Sanchez has a flower bed
   with a length of 10 meters and a width
   of 5 meters. If he can only change the
   width of the flower bed, describe what
   he can do to increase the perimeter by
   12 meters.

Use any strategy to solve Exercises 6–12.

6. SPORTS Every 12 times at bat, Shim hits the
   ball an average of 3 times. About how
   many times will he hit the ball after 20 times
   at bat? 40? 84?

Times at Bat Number of Hits

12 3

20?

40?

84?

7. NUMBERS A number is halved. Then three
   is subtracted from the quotient, and 5 is
   multiplied by the difference. Finally, 1 is
   added to the product. If the ending
   number is 26, what was the beginning
   number?


8. PRIZES By reaching into a bag that has
   letters A, B, and C, George will select
   three letters without replacing them.
   In how many possible ways could the
   letters be drawn?


9. HEALTH The human body is about _^7
   10
   water.
   About how much would a person weigh if
   he or she had 70 pounds of water weight?


10. FINANCIAL LITERACY The ratio of Julio’s
    money to Marcus’s money was 7 : 10. After
    Julio bought 4 books at $4.50 each, the ratio
    of Julio’s money to Marcus’s money was
    1 : 4. Use a bar diagram to find how much
    money Julio and Marcus have left.


11. GEOMETRY What is the next figure in the
    pattern below?


12. BASKETBALL Last basketball season, Simon
    had four less than twice the number of free
    throws Amit had. Simon had 48 free
    throws. How many free throws did Amit
    have last season?


13. E WRITE MATH Write a real-world
    problem that can be solved by drawing
    a diagram. Then solve the problem.

282_283_C05_L2_PSI_895130.indd 283 12/29/09 1:00 PM