Name_________________________________________________________
Date __________
Rewriting Equations and Formulas
1.4
For use with Activity 1.4
Essential Question How can you use a formula for one measurement to
write a formula for a different measurement?
1
ACTIVITY: Using Perimeter and Area Formulas
Work with a partner.
a. •
Write a formula for the perimeter P of
a rectangle.
•
Solve the formula for w.
•
Use the new formula to find the width
of the rectangle.
b. •
A = 10 in.2
h
b=
c. •
P = 19 in.
w
= 5.5 in.
Write a formula for the area A of a triangle.
•
Solve the formula for h.
•
Use the new formula to find the height
of the triangle.
5
in.
2
Write a formula for the circumference C of
a circle.
•
Solve the formula for r.
•
Use the new formula to find the radius of
the circle.
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C = 8π cm
rr
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Name _________________________________________________________ Date _________
1.4
Rewriting Equations and Formulas (continued)
•
Write a formula for the area A.
•
Solve the formula for h.
•
Use the new formula to find the height.
d.
e.
b = 4 in.
A = 56 m2
A = 15 in.2
h
B = 6 in.
2
h
b=8m
ACTIVITY: Using Volume Formulas
Work with a partner.
a. •
V = 60 in.3
Write a formula for the volume V of a prism.
•
Solve the formula for h.
•
Use the new formula to find the height of
the prism.
h
B = 12 in.2
16
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Name_________________________________________________________
1.4
Date __________
Rewriting Equations and Formulas (continued)
•
Write a formula for the volume V.
•
Solve the formula for B.
•
Use the new formula to find the area of the base.
b.
c.
V = 48 ft3
V = 48π cm3
h = 9 ft
h = 12 cm
B
B
d. •
Write a formula for the volume V
of a cone.
•
Solve the formula for h.
•
Use the new formula to find the
height of the cone.
V = 18π m3
h
B = 9π m2
What Is Your Answer?
3. IN YOUR OWN WORDS How can you use a formula for one measurement
to write a formula for a different measurement? Give an example that is
different from the examples on these three pages.
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Name _________________________________________________________ Date _________
1.4
Practice
For use after Lesson 1.4
Solve the equation for y.
1. 2 x + y = − 9
2. 4 x − 10 y = 12
3. 13 =
1
y + 2x
6
Solve the equation for the bold variable.
4. V = Awh
5.
f =
1
(r + 6.5)
2
7. The formula for the area of a triangle is A =
6. S = 2π r 2 + 2π rh
1
bh .
2
a. Solve the formula for h.
b. Use the new formula to find the value of h.
A = 54 in.2
h
12 in.
18
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