Math 1 · Unit 4 · Lesson 1 · part 1 of 6
The Words We Use
The vocabulary for this lesson, in one place.
Words we use
| Word | Plain English | What you do |
|---|---|---|
| Parallel | Lines that never cross, always the same distance apart. On a graph: the same slope, different y-intercepts. | Compare m. Same m and different b means parallel. |
| Slope (m) | The steepness and direction: rise over run, how much y changes for each step of x. | Read it off y = mx + b, or count it on the graph. |
| y-intercept (b) | Where the line crosses the y-axis, the value when x is 0. | Parallel lines differ here. To write a parallel line through a point, keep m and use the point to find b. |
| Same line | Same slope and same y-intercept: one line written twice. | If both m and b match, it is not a pair of parallel lines. |
| Family of lines | All lines share y = mx + b. Parallel lines are the members with the same m. | Changing b slides a line; every slide is a parallel line. |
| Vertical, horizontal | Straight up and down (no slope), or flat (slope 0). | Any two vertical lines are parallel; any two horizontal lines are parallel. |