Example 4 Using an Irrational Number in Real Life

WAVESFor large ocean waves, the wind speed s (in knots) and the height h (in feet) of the waves are related by the

model . If the waves are about 9.5 feet tall,

what is the wind speed? (1 knot is equivalent to about 1.15 miles per hour.)

0.019h=s

0.019h

=s

SOLUTION

Write given model.

Example 4 Comparing Real Numbers

0.0199.5

= Substitute 9.5 for h.

= Divide.500

≈ Approximate square root.22.4

ANSWER The wind speed is about 22 knots.

Guided Practice

In Example 4, suppose the waves grow to about 15 feet tall. What is the wind speed rounded to the nearest knot?

for Example 4

ANSWER 28 knots

13. WHAT IF?