Example 5 Using a Calculator
Evaluate the square root. Round to the nearest tenth if necessary.
a. 56.25– c. 1256–
b. [ ] 8 2.828427125 2.8
SOLUTION
Keystrokes Display Answer
a. [ ] 56.25 7.5– 7.5–
b. 8
c. 1256 35.44009029– 35.4–[ ]
Example 6 Using a Square Root in Real Life
The model gives the speed needed to keep riders pinned to the wall of an amusement park ride. In the model, s is the speed (in meters per second) and r is the radius of the ride (in meters). Find the speed necessary to keep riders pinned to the wall of a ride that has a radius of 2.61 meters.
AMUSEMENT PARKS
4.95s = r
SOLUTION
Write model for speed of the ride.4.95s = r
Substitute 2.61 for r.4.95= 2.61
Example 6 Using a Square Root in Real Life
ANSWER
The speed should be about 8 meters per second.
Multiply.8.019=
Approximate the square root using a calculator.
4.95( )1.62≈
Guided Practice
10. Use a calculator to evaluate to the nearest tenth.
for Examples 5 and 6
ANSWER 15.4
ANSWER 9.3 m per sec
236
11. WHAT IF?In Example 6, what is the speed necessary to keep riders pinned to the wall of a ride that has a radius of 3.56 meters? Round your answer to the nearest tenth of a meter per second.