Lorraine hits a golf ball into the air. It lands 60 feet away from her. At its highest point, the ball is 30 feet in the air.

Desmos Link

(6 points)
This scenario would best be represented by a
Quadratic
equation.

The ball lands 60 feet away from her would represent the
x-intercept of the graph
. Half of this distance would be axis of symmetry. That would make the vertex
(30,30)

The ball starts at how many feet away from Lorraine?
0
So another point on the graph would be

Using the information, the only value that is not given and needs to be found is the

Question 10
What is the equation for this scenario?

What is the height of the golf ball when it is 15 feet away from Lorrain?

(2 points)
The equation is f(x) =
𝑓
(
𝑥
)

=

(answer using fractions and do not include grouping symbols)

The height of the ball when it is 15 feet away from Lorraine is feet in the air. (round to the nearest te

1 answer

To represent the scenario of the golf ball hit by Lorraine, we can derive a quadratic function based on the given information.

Information Given:

  • The ball lands 60 feet away: x-intercepts = (0, 0) and (60, 0)
  • The highest point of the ball is 30 feet: y-coordinate of the vertex = 30 feet
  • The axis of symmetry is at half the distance to the landing point: axis of symmetry = 30 feet (at x = 30)

Step-by-step Breakdown:

  1. Vertex Form of the Quadratic Equation: The general form of a quadratic equation can be presented as: \[ f(x) = a(x - h)^2 + k \] where (h, k) is the vertex.

    Based on the highest point (vertex) at (30, 30): \[ f(x) = a(x - 30)^2 + 30 \]

  2. Finding 'a': Since we know the ball lands on the x-axis at (0, 0), we can use this point to find the value of 'a'. \[ 0 = a(0 - 30)^2 + 30 \] \[ 0 = a(900) + 30 \] \[ a(900) = -30 \] \[ a = -\frac{30}{900} = -\frac{1}{30} \]

  3. Final Equation: Substituting 'a' back into the vertex form: \[ f(x) = -\frac{1}{30}(x - 30)^2 + 30 \] For a standard form or simplified version (using vertex coordinates): \[ f(x) = -\frac{1}{30}(x^2 - 60x + 900) + 30 \] Expanding it gives: \[ f(x) = -\frac{1}{30}x^2 + 2x \]

  4. Finding the Height when x = 15: Substitute x = 15 into the equation: \[ f(15) = -\frac{1}{30}(15)^2 + 2(15) \] \[ = -\frac{1}{30}(225) + 30 \] \[ = -7.5 + 30 \] \[ = 22.5 \]

Summary Answers:

  • Equation of the scenario: \[ f(x) = -\frac{1}{30}x^2 + 2x \]
  • Height of the ball when it is 15 feet away from Lorraine: \[ \text{Height} \approx 23 \text{ feet (rounded to the nearest whole number)} \]

You may write the equation and height in the format you need. If you need further assistance, please let me know!