Parallel and perpendicular lines in linear functions

All in One Place

Everything you need for better grades in university, high school and elementary.

Learn with Ease

Made in Canada with help for all provincial curriculums, so you can study in confidence.

Instant and Unlimited Help

Get the best tips, walkthroughs, and practice questions.

    • Definition of Parallel and Perpendicular Lines
    • How does that relate to slope?
  1. Determine whether the three points A (-2,-1), B(0,4) & C(2,9) all lie on the same line.
    1. Determine the following slopes are parallel, perpendicular, or neither.
      i) m1=25,m2=25 m_1 = {2 \over 5}, m_2= {2 \over 5}

      ii) m1=15,m2=51m_1 = {1 \over5} , m_2 = - {5 \over 1}

      iii) m1=47,m2=1221m_1 = {4 \over 7}, m_2 = {12 \over 21}

      iv) m1=m_1 = undefined, m2=0 m_2 = 0

      v) m1=mn1;m2=m1bm_1 =mn^{-1}; m_2 =-m^{-1}b
      1. Given the points of two lines, determine when the lines are parallel, perpendicular or neither.
        1. Line 1: (3,2) & (1,4); Line 2: (-1,-2) & (-3,-4)
        2. Line 1: (5,6) & (7,8); Line 2: (-5,-6) & (-7,-8)
        3. Line 1: (0,4) & (-1,2); Line 2: (-3,5) & (1,7)
      2. Show that the points A(-3,0), B(1,2) and C(3,-2) are the vertices of a right triangle.
        1. Show that the points A(-1,-1), B(3,0), C(2,4) and D(-2,3) are the vertices of a square.
          Topic Notes
          Parallel lines are lines with identical slope. In other words, these lines will never cross each other. Perpendicular lines will always pass through each other and form right angles at the interception. In this lesson, we will learn how to use information such as, points in lines and their slopes, to determine whether the lines are parallel, perpendicular or neither.
          - identical slope so they never intersect each other, unless overlapped.

          - two lines form right angles to each other when they intersect. If the slope of first line is ab {a \over b} , the slope of perpendicular line is the slope of perpendicular line is ba - {b \over a} . The product of the two slopes is -1.