Algebra 1 Common Core Student Edition, Grade 8-9

Problem 4 Using Scale Models

Science A giant model heart is shown below. The heart is the ideal size for a

person who is 170 ft tall. About what size would you expect the heart of a man

who is 6 ft tall to be?

is this problem like
ones you have seen?
Yes. Scale m odel
problem s are like scale
drawing problems, so you
can w rite a p ro p o rtio n
like you did to fin d the
h e ig h t o f th e b u ild in g in
Problem 2.

h e ig h t o f g ia n t h e a r t _ h e ig h t o f g ia n t p e r s o n

h e ig h t o f m a n ’s h e a r t height of m an Write a proportion.

^ Substitute.

14(6) = 170x Cross Products Property

0.49 = x Divide each side by 1 70 and simplify.

The size of the m an 's h e a rt w ould be a b o u t 0.49 ft, or 5.9 in.

G o t It? 4. A scale m odel of a b uilding is 6 in. tall. I h e scale of th e m odel is 1 i n. : 50 ft.

How tall is th e actual building?

Lesso n Ch eck

Do you kn o w HO W?

1. Photocopies You use a p h o to co p ier to enlarge a
   drawing of a right triangle w ith a base of 13 cm an d a
   height of 7 cm. The enlarged triangle has a height of
   17.5 cm.
   a. W hat is th e base of th e enlarged triangle?
   b. W hat is th e scale of th e enlargem ent?


2. Maps The scale of a m ap is 1 c m : 75 km. W hat is
   the actual d istance b etw een two tow ns th a t are 3 cm
   apart on th e m ap?

Do you UNDERSTAND?

3. Vocabulary Suppose AMNP
   identify corresponding parts?

MATHEMATICAL

PRACTICES

• ARST. How can you

4. Reasoning Suppose AABC ~ ATUV. Determine
   w h e th e r each p air of m easures is equal.
   a. the measures of A A and AT
   b. th e perim eters of th e two triangles
   c. th e ratios of th e sides an d ^


5. Reasoning The scale of a m ap is 1 i n. : 100 mi. Is the
   actual d istance b etw een two tow ns 100 tim es th e m ap
   distance b etw een th e two towns? Explain.

c

PowerAlgebra.com Lesso n 2-8 Pr o p o r t i o n s an d Si m i l ar Fi g u r es 133