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Parallel and Perpendicular Slope Investigation

Parallel Line Slope Conjecture

Make sure parallel line and parallel line slope are both checked above. Move the slope slider (m) back and forth. What do you notice about the slopes of the parallel lines?

Parallel Lines and Y-Intercepts

Move the Y-intercept slider this time. What if the two lines have the same y-intercept? What do you notice? Can parallel lines have the same y-intercept?

Perpendicular Slope Conjecture Investigation Q1

Uncheck the parallel boxes and check the perpendicular boxes. Type the slope of the pink line as a fraction in simplest form then type the slope of the green (perpendicular) line as a fraction in simplest form. Use the grid to help you. You may need to zoom in to see the grid better.

Perpendicular Slope Conjecture Investigation Q2

Move the slope slider and type the slope of the pink line and the green line as fractions in simplest form. (No decimals)

Perpendicular Slope Conjecture Investigation Q3

Once more, move the slope slider and type the slope of the pink line and the green line as fractions in simplest form.

Perpendicular Slope Conjecture

If two lines are perpendicular, then their slopes are _____________________ and ________________________.

Perpendicular Lines and Y-Intercepts

Move the y-intercept slider around. Can perpendicular lines have the same y-intercept?

Check for understanding #1

Suppose line l is parallel to line m, if the slope of line l is 4/5, what is the slope of line m?

Check for understanding #2

Suppose line l is perpendicular to line n, if the slope of line l is 2/3, what is the slope of line n?

Check for understanding #3

Suppose line s is perpendicular to line t, if the slope of line s is -4, what is the slope of line t?

Extension

Suppose line y is perpendicular to line z, if the slope of line y is 0, what is the slope of line z? (What do the lines look like?)