1. EXAMPLE 3 Using an Irrational Number Waves For large ocean waves, the wind speed s in knots and the height of the waves h in feet are related by the equation s =. If the waves are about 9.5 feet tall, what must the wind speed be? ( 1 knot is equivalent to 1.15 miles per hour.) 0.019 h

2. EXAMPLE 3 Using an Irrational Number The wind speed is about 22 knots. ANSWER 22.4 Approximate square root. 500 = Divide. 0.019 9.5 = Substitute 9.5 for h. 0.019 h = Write original equation. SOLUTION

3. GUIDED PRACTICE for Example 4 11. What If? In Example 4, suppose the waves grow to about 15 feet tall. What is the wind speed rounded to the nearest knot? ANSWER The wind speed is about 28 knots