Features of a parabola from its graph or its equation

Answer Key - Grade 9 Math Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Noah tosses a water balloon up. Its height is y = -5t² + 10t + 3 after t seconds, with y in meters. What is its greatest height, in meters?

   8
2. 2.

   Pia's toy frog hops. Its height is y = -x² + 10x at x cm from the start, with y in cm (it lands on a cushion). What is its greatest height, in centimeters?

   25
3. 3.

   Ren's swing seat is y = x² - 6x + 14 above the ground at x across, all in decimeters. What is its lowest height, in decimeters?

   5

4. Read this first

   Use the table

   input x	output y
   0	1
   1	16
   2	21
   3	16
   4	1

5. 4.

   Tala kicks a ball up. The table gives its height in meters after x seconds. What does the vertex of this graph tell you?

   • The ball lands after 2 seconds.
   • The ball is highest, 2 m, after 21 seconds.
   • The ball is highest, 21 m, after 2 seconds.
   • The ball starts at 21 m.
6. 5.

   Zee's toy car rolls through a dip in its track. The table gives its height in cm after x seconds. What does the vertex of this graph tell you?

   • The car is lowest, 2 cm, after 3 seconds.
   • The car is lowest, 3 cm, after 2 seconds.
   • The car starts at 2 cm.
   • The car touches the ground after 3 seconds.
7. 6.

   Ari measures a fountain's arc. The table gives the water's height in feet, x feet from the spout. What does the vertex of this graph tell you?

   • The water is highest, 9 feet, 3 feet from the spout.
   • The water lands 3 feet from the spout.
   • The water starts at 9 feet.
   • The water is highest, 3 feet, 9 feet from the spout.
8. 7.

   Bo's kite dips in the wind, then rises. The table gives its height in meters after x minutes. What does the vertex of this graph tell you?

   • The kite touches the ground after 2 minutes.
   • The kite starts at 5 m.
   • The kite is lowest, 2 m, after 5 minutes.
   • The kite is lowest, 5 m, after 2 minutes.
9. 8.

   Jun's table for a map valley has the rows -6 | 7 and 2 | 7. Where is the axis of symmetry? Write the number after x =.

   -2
10. 9.

    Kira's table for a rainbow arc has the rows 1 | 10 and 8 | 10 (the middle rows washed out). Where is the axis of symmetry? Write the number after x =.

    4.5
11. 10.

    Luz's table for a bowl has the rows -7 | -11 and -1 | -11. Where is the axis of symmetry? Write the number after x =.

    -4