Page 57 - Math Course 2 (Book 1)

Real Number System

REAL WORLD EXAMPLE Real World Example

HANG GLIDING ELECTRICITY
s 2 When a current of I amperes f ows through a
The formula for aspect ratio R is , where
R=
A
s is the wingspan in feet and A is the area of the light bulb with resistance R ohms, electrical en-
wing. What is the aspect ratio of a hang glider if ergy is converted to heat at a power of P watts.
the wingspan is 16 feet and the area of the wing is The power is related to the current and resistance
2
40 square feet? by the equation P = I R. What is the current for a
light bulb of power 25 watts and resistance of 7.3
ohms? Round to the nearest hundredth.

s 2
R = Write the formula.
A A. 0.47 amps
B. 1.85 amps
(16) 2 Replace s with 16 and A with 40.
R = C. 2.64 amps
40
D. 3.42 amps
256
R = 16 •16 = 256
40

R = 6.4 Divide. Answer

Answer 6.4

Your Turn!

Solve Equations

2
Solve the equation m = 81. Round to the nearest
tenth, if necessary.

A. 8
B. 8 and –8
C. 9
D. 9 and –9

Answer

2
Solve the equation h = 24. Round to the nearest
tenth, if necessary.

A. 4.899 and –4.899
B. 4.9
C. 4.9 and –4.9
D. 5 and –5

Answer

49