parallel and perpendicular lines
TRANSCRIPT
Parallel and Perpendicular Lines
MAP TAP 2003-2004 Parallel and Perpendicular Lines 2
Teacher Page Content: Write the equation of a parallel or
perpendicular line to a given line, in slope intercept form.
Grade Level: Algebra 2/Geometry Creator: Don Sutcliffe Other – Print slides 13-20 as a handout for
students to take notes.
MAP TAP 2003-2004 Parallel and Perpendicular Lines 3
Parallel Lines Two non-vertical lines are parallel if
and only if their slopes are equal. If l1║l2, then m1= m2.
If m1= m2, then l1║l2.
l1 l2
m1 m2
MAP TAP 2003-2004 Parallel and Perpendicular Lines 4
Write the equation of the line that passes through (3,6) and is parallel to y = 2/3x+2.
m = 2/3 and the point is (3,6)
y = mx+b
6 = 2/3(3)+b
6 = 2+b
4 = b
y = 2/3x+4
MAP TAP 2003-2004 Parallel and Perpendicular Lines 5
Write the equation of the line that passes through (4,-5) and is parallel to y = -2x-4.
m = -2 and the point is (4,-5)
y = mx+b
-5 = -2(4)+b
-5 = -8+b
3 = b
y = -2x+3
MAP TAP 2003-2004 Parallel and Perpendicular Lines 6
Write the equation of the line that passes through (-6,4) and is parallel to y=1/3x-1.
m=1/3 and the point is (-6,4)
y =1/3x+6
MAP TAP 2003-2004 Parallel and Perpendicular Lines 7
Perpendicular Lines Two non-vertical lines are
perpendicular if and only if the product of their slopes is -1. If l1┴l2, then m1 ● m2= -1.
If m1● m2 = -1, then l1┴l2.l1
l2
m2m1
Slopes are negative reciprocals
MAP TAP 2003-2004 Parallel and Perpendicular Lines 8
Write the equation of the line that passes through (6,-5) and is perpendicular to y = 2x+3.
m = -1/2 and the point is (6,-5)
y = mx+b
-5 = -1/2(6)+b
-5 = -3+b
-2 = b
y = -1/2x-2
MAP TAP 2003-2004 Parallel and Perpendicular Lines 9
Write the equation of the line that passes through (6,-7) and is perpendicular to y = 2/3x+1.
m = -3/2 and the point is (6,-7)
y = mx+b
-7 = -3/2(6)+b
-7 = -9+b
2 = b
y = -3/2x+2
MAP TAP 2003-2004 Parallel and Perpendicular Lines 10
Write the equation of the line that passes through (-4,-3) and is perpendicular to y = x+6.
m = -1 and the point is (-4,-3)
y = -x-7
MAP TAP 2003-2004 Parallel and Perpendicular Lines 11
End Show
MAP TAP 2003-2004 Parallel and Perpendicular Lines 12
Parallel Lines Two non-vertical lines are parallel if
and only if their slopes are equal. If l1║l2, then m1= m2.
If m1= m2, then l1║l2.
l1 l2
m1 m2
MAP TAP 2003-2004 Parallel and Perpendicular Lines 13
Write the equation of the line that passes through (3,6) and is parallel to y = 2/3x+2.
m = _____ and the point is (__,__)
y = mx+b
MAP TAP 2003-2004 Parallel and Perpendicular Lines 14
Write the equation of the line that passes through (4,-5) and is parallel to y = -2x-4.
m = ____ and the point is (__,__)
MAP TAP 2003-2004 Parallel and Perpendicular Lines 15
Write the equation of the line that passes through (-6,4) and is parallel to y=1/3x-1.
m=___ and the point is (__,__)
MAP TAP 2003-2004 Parallel and Perpendicular Lines 16
Perpendicular Lines Two non-vertical lines are
perpendicular if and only if the product of their slopes is -1. If l1┴l2, then m1 ● m2= -1.
If m1● m2 = -1, then l1┴l2.l1
l2
m2m1
MAP TAP 2003-2004 Parallel and Perpendicular Lines 17
Write the equation of the line that passes through (6,-5) and is perpendicular to y = 2x+3.
m = ___ and the point is (__,-__)
MAP TAP 2003-2004 Parallel and Perpendicular Lines 18
Write the equation of the line that passes through (6,-7) and is perpendicular to y = 2/3x+1.
m = ____ and the point is (__, __)
MAP TAP 2003-2004 Parallel and Perpendicular Lines 19
Write the equation of the line that passes through (-4,-3) and is perpendicular to y = x+6.
m = ___ and the point is (__,__)