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.