Math 1 · Unit 4 · Lesson 3 · part 3 of 5
Choose the move: parallel or perpendicular through a point
Now the mixed skill: write a line parallel or perpendicular to a given line through a point, choosing the...
Choose the move: parallel or perpendicular through a point
Now the mixed skill: write a line parallel or perpendicular to a given line through a point, choosing the right move yourself. The only difference is the first step.
Parallel through a point
Keep m. Then put the point in, solve for b, write y = mx + b.
Parallel to y = −3x + 4 through (1, 2): m = −3. 2 = −3 + b, b = 5. y = −3x + 5.
Perpendicular through a point
Take the negative reciprocal of m. Then put the point in, solve for b, write y = mx + b.
Perpendicular to y = −3x + 4 through (1, 2): new m = 13. 2 = 13 + b, b = 53. y = 13x + 53.
Say the move before you make itParallel: same m. Perpendicular: flip and change the sign. Everything after that is Unit 3.