### Home > INT3 > Chapter 9 > Lesson 9.1.2 > Problem 9-15

David Longshot is known for his long golf drives. At the driving range he hit a golf ball 250 yards and estimated that the ball reached a maximum height of 15 yards. Homework Help ✎

Use a quadratic function to model the path of the golf ball.

David’s brother, Dwayne, was also at the driving range and hit a ball according to the table at the right. Which ball traveled farther horizontally? Which ball went higher in the air?

Horizontal distance (yd)

Height (yd)

0

0

20

5.5

60

13.5

180

13.5

220

5.5

Recall the quadratic equation:

*f*(*x*) = *a*(*x* − *h*)^{2} + *k*

Use the maximum-point coordinates to replace some variables in the equation above.

Substitute (0, 0) for *x* and *y* to solve for the slope.

Sketch Dwayne's projection and notice how much farther his ball can travel past 220 yards.

David's ball traveled farther at 250 yards while Dwayne's ball traveled 240 yards.

How high did Dwayne's ball go?