The complex plane, and the absolute value of a complex number

Answer Key - Grade 11 Math Worksheet - Building Confidence

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

1. 1.

   Jun drops a pin on a grid map of the complex plane, as in the figure. Which complex number is the pin, in a + bi form?

   4 − i
2. 2.

   Kira marks a spot on the complex plane, as in the figure. Which complex number is it, in a + bi form?

   -3 + 5i
3. 3.

   Luz's robot parks at the dot in the figure. Which complex number is the dot, in a + bi form?

   -6i
4. 4.

   Milo plots a puzzle answer, as in the figure. Which complex number is the dot, in a + bi form?

   -2 − 7i
5. 5.

   Pia plots 5 − 4i for a math club poster. Where is the point?

   • 4 left of 0 and 5 up
   • 5 right of 0 and 4 up
   • 5 left of 0 and 4 down
   • 5 right of 0 and 4 down
6. 6.

   Ren marks -1 − 6i on the board's complex plane. Where is the point?

   • 6 left of 0 and 1 down
   • 1 left of 0 and 6 up
   • 1 left of 0 and 6 down
   • 1 right of 0 and 6 down
7. 7.

   Tala's robot is sent to 2 + 7i. Where is the point?

   • 2 right of 0 and 7 up
   • 2 left of 0 and 7 up
   • 2 right of 0 and 7 down
   • 7 right of 0 and 2 up
8. 8.

   Zee measures how far a pin at -9 + 40i is from 0 on the grid map. What is |-9 + 40i|?

   41
9. 9.

   Esme's robot rolls straight from 0 to 16 − 63i. What is |16 − 63i|, the distance from 0?

   65
10. 10.

    Kira finds the absolute value of 28 + 45i, its distance from 0. What is |28 + 45i|?

    53