Parallel and perpendicular lines: compare slopes, and write the line through a point

Answer Key - Grade 9 Math Worksheet - Building Confidence

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

1. 1.

   Line A has the rows 0 | 2, 1 | 5, 2 | 8. Esme's line B is parallel to A and starts at 0 | 7. What is B's output when x = 1?

   10
2. 2.

   Line A has the rows 0 | 4, 1 | 6, 2 | 8. Ren's line B is parallel to A and starts at 0 | 9. What is B's output when x = 1?

   11
3. 3.

   Line A has the rows 0 | 1, 1 | 5, 2 | 9. Kira's line B is parallel to A and starts at 0 | 6. What is B's output when x = 1?

   10
4. 4.

   Line A has the rows 0 | 3, 1 | 8, 2 | 13. Zee's line B is parallel to A and starts at 0 | 2. What is B's output when x = 1?

   7
5. 5.

   Milo's line A rises 2 for every 3 across (slope 2/3). A perpendicular line swaps those two numbers and changes the sign. What is the slope of the perpendicular line?

   -3/2
6. 6.

   Bo's line A rises 3 for every 4 across (slope 3/4). A perpendicular line swaps those two numbers and changes the sign. What is the slope of the perpendicular line?

   -4/3
7. 7.

   Pia's line A falls 4 for every 5 across (slope -4/5). A perpendicular line swaps those two numbers and changes the sign. What is the slope of the perpendicular line?

   5/4
8. 8.

   Jun's line A rises 5 for every 2 across (slope 5/2). A perpendicular line swaps those two numbers and changes the sign. What is the slope of the perpendicular line?

   -2/5
9. 9.

   Line A has slope 2, and Luz's line B has slope 1/2. What do the two slopes multiply to?

   1
10. 10.

    Line A has slope 2/3, and Ari's line B has slope -3/4. What do the two slopes multiply to?

    -1/2