How stretched is a conic? Eccentricity

Answer Key - Grade 11 Math Worksheet - Building Confidence

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

1. 1.

   Jun draws an ellipse with a string and two pins at the foci. The long axis is 10 cm, and each pin is 4 cm from the center. What is the eccentricity e?

   4/5
2. 2.

   Kira draws an ellipse with a string and two tacks at the foci. The long axis is 26 cm, and each tack is 12 cm from the center. What is the eccentricity e?

   12/13
3. 3.

   Luz draws an ellipse with a hose and two stakes at the foci. The long axis is 20 ft, and each stake is 6 ft from the center. What is the eccentricity e?

   3/5
4. 4.

   Milo draws an ellipse with a rope and two posts at the foci. The long axis is 34 ft, and each post is 8 ft from the center. What is the eccentricity e?

   8/17
5. 5.

   Earth's orbit around the Sun has eccentricity e = 0.017. Noah labels a poster of the solar system. What kind of conic is Earth's orbit?

   • circle
   • ellipse
   • hyperbola
6. 6.

   Tala rides a Ferris wheel whose rim is a conic with eccentricity e = 0. What kind of conic is the rim?

   • circle
   • parabola
   • ellipse
7. 7.

   Zee sketches an oval rug as an ellipse with a = 5 and b = 4, half the long and short axes. How far is each focus from the center?

   3
8. 8.

   Jun sketches an oval kite as an ellipse with a = 13 and b = 5, half the long and short axes. How far is each focus from the center?

   12
9. 9.

   Kira sketches an oval table top as an ellipse with a = 10 and b = 8, half the long and short axes. How far is each focus from the center?

   6
10. 10.

    Luz sketches an oval mirror as an ellipse with a = 17 and b = 15, half the long and short axes. How far is each focus from the center?

    8