Do you think that all perpendicular slopes are related in the way you observed in problem 1-69? Investigate this idea by drawing three different lines with slope triangles on graph paper. Use slopes 1, 1/3 and 3/4 . Use tracing paper to rotate each line with its slope triangle 90º , either counterclockwise () or clockwise (). Find the slope of each new line. How does the slope of each rotated line compare to the slope of its original line? Share any patterns you find with your teammates. Use patterns from the work you have done to describe the general relationship of the slopes of perpendicular lines. That is, if you have two perpendicular lines and know the slope of one, how can you find the slope of the other?