writing equations of lines and midpoint
TRANSCRIPT
1 Notes Writing Equations of Lines.notebook
1
November 09, 2016
Aug 156:17 PM
Writing Equations of Lines
and MidpointMGSE9‐12.G.GPE.5 Prove the slope criteria for parallel and perpendicular lines and usethem to solve geometric problems (e.g., find the equation of a line parallel orperpendicular to a given line that passes through a given point).
Aug 156:19 PM
What am I learning today?
How to write equations of lines given specific
conditions
How will I show that I learned it?
Write the equation of a line in slopeintercept
form that satisfies a set of conditions
1 Notes Writing Equations of Lines.notebook
2
November 09, 2016
Nov 811:37 AM
Three forms for linear equations
Standard: ax + by = c
SlopeIntercept: y = mx + b
PointSlope: y y1 = m(x x1)
Aug 14 6:54 PM
To write the equation of a line, you must be given one of the following sets of information:
1) The slope and the y‐intercept
2) The slope and a point on the line
3) Two points on the line
1 Notes Writing Equations of Lines.notebook
3
November 09, 2016
Aug 14 6:57 PM
GIVEN SLOPE AND Y‐INTERCEPT
Plug m and b in to slope‐intercept form
Write an equation for each of the following lines:
y‐intercept of 4, slope of
slope of , y‐intercept of ‐7
Aug 14 7:11 PM
GIVEN SLOPE AND ANY POINT ON THE LINE
Point‐Slope Form:
Using point‐slope form:
1) Plug in slope for m
2) Plug in point for (x1 , y1)
3) Solve for y
1 Notes Writing Equations of Lines.notebook
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November 09, 2016
Nov 1010:43 AM
passes through (2, 3) with a slope of
Nov 1010:44 AM
passes through (‐3, 4) with a slope of
1 Notes Writing Equations of Lines.notebook
5
November 09, 2016
Nov 1010:45 AM
passes through (5, 6) with a slope of
Aug 17 7:57 AM
GIVEN TWO POINTS ON THE LINE
Steps:
1) Use the given points to find the slope
2) Plug in either point, along with the slope fromstep 1, into the point‐slope form
3) Solve for y
1 Notes Writing Equations of Lines.notebook
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November 09, 2016
Nov 1010:48 AM
passes through (‐2, ‐1) and (3, 4)
Aug 17 8:00 AM
passes through (1, 5) and (4, 2)
1 Notes Writing Equations of Lines.notebook
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November 09, 2016
Aug 17 8:00 AM
passes through (3, 0) and (‐3, 1)
Aug 17 8:00 AM
passes through (2, ‐5) and (‐3, ‐5)
1 Notes Writing Equations of Lines.notebook
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November 09, 2016
Aug 17 8:00 AM
passes through (3, 7) and (3, ‐1)
Aug 11 6:07 PM
Two lines are PARALLEL if they lie in the same plane and never intersect
In order for two lines to never intersect, then they must be "rising" and "running" at the exact same rate.Therefore, if two lines have equal slopes, then they will be parallel.
1 Notes Writing Equations of Lines.notebook
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November 09, 2016
Nov 1010:54 AM
In order for two lines to intersect at a 90o angle, as one is "rising", then the other is "running" at the same rate, and vice versa. However, the directions in which they are moving will be different.Therefore, if two lines have slopes that are negative reciprocals of each other, then they will be perpendicular.
Two lines are PERPENDICULAR if they intersect to form a right angle
Feb 24:04 PM
Determine which of the lines, if any, are parallel, and which are perpendicular
line a: through (‐4, 1) and (‐6, 7)
line b: through (‐7, ‐5) and (1, 11)
line c: through (2, 5) and (4, 9)
line d: through (4, 3) and (10, 5)
1 Notes Writing Equations of Lines.notebook
10
November 09, 2016
Nov 1010:56 AM
passes through (2, ‐3) and is perpendicular to the line
Oct 2211:09 PM
passes through (‐3, 4) and is parallel to
1 Notes Writing Equations of Lines.notebook
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November 09, 2016
Oct 2211:11 PM
passes through (5, 6) and is parallel to
Oct 2211:15 PM
passes through (3, ‐5) and is perpendicular to the line through (1, 4) and (3, ‐2)
1 Notes Writing Equations of Lines.notebook
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November 09, 2016
Nov 115:30 AM
In ABC, A(‐3, 4), B(5, ‐2), and C(‐4, ‐5).Write the equation of the altitude to AB.
Oct 279:33 PM
How can we find the point that divides a segment in half?
0 22
‐4 38
Formula:
1 Notes Writing Equations of Lines.notebook
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November 09, 2016
Oct 279:33 PM
Find the coordinate of the point that is ½ of the way from A to B
12 49
‐143 51
B
B
A
A
Sep 20 7:59 AM
THE MIDPOINT FORMULA
Given two points, A(x1, y1) and B(x2, y2), the MIDPOINT of AB can be found using the formula:
1 Notes Writing Equations of Lines.notebook
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November 09, 2016
Sep 20 8:04 AM
Find the coordinates of the midpoint of AB
A
B
Sep 20 8:07 AM
If the midpoint of AB falls at (7, 9), and point A is located at (‐2, 4), then find the coordinates of B
1 Notes Writing Equations of Lines.notebook
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November 09, 2016
Nov 115:30 AM
In ABC, A(‐3, 2), B(9, 4), and C(5, 12).Write the equation of the median from C.
Nov 115:30 AM
In ABC, A(‐6, 2), B(8, 4), and C(18, 12).Write the equation of the midsegment that is parallel to BC.
1 Notes Writing Equations of Lines.notebook
16
November 09, 2016
Nov 115:30 AM
In ABC, A(2, 3), B(12, 5), and C(9, 8).Write the equation of the perpendicular bisector of AB.
Nov 511:23 AM
Homework:
Writing Equations of Lines WS