5.1 warm-up
DESCRIPTION
5.1 warm-up. Suppose the line shown is translated 2 units to the left and 1 unit down. Which point would lie on the translated line ? a. (-2,-2) b. (-1,1) c. (0,2) d. (2,3). y. 3. 2. 1. -3 -2 -1 0 1 2 3 x. -3. 6. Pardekooper. - PowerPoint PPT PresentationTRANSCRIPT
Suppose the line shown is translated 2 units to the left and 1 unit down. Which point would lie on the translated line ?
a. (-2,-2)
b. (-1,1)
c. (0,2)
d. (2,3)
5.1 warm-up
6
-3 -2 -1 0 1 2 3 x
-3
12
3 y
What makes a quadrilateral a parallelogram?
• 1. Opposite sides are congruent
• 2. Opposite angles are congruent
• 3. Diagonals bisect each other
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Now, we look at some theorems
• If both pairs of opposite sides of If both pairs of opposite sides of a quadrilateral are congruent, a quadrilateral are congruent,
then the quadrilateral is a then the quadrilateral is a parallelogram.parallelogram.
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Now, we look at some theorems
• If both pairs of opposite angles If both pairs of opposite angles of a quadrilateral are congruent, of a quadrilateral are congruent,
then the quadrilateral is a then the quadrilateral is a parallelogram.parallelogram.
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Now, we look at some theorems
• If the diagonals of a quadrilateral If the diagonals of a quadrilateral bisect each other, then the bisect each other, then the
quadrilateral is a parallelogram,quadrilateral is a parallelogram,
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Now, we look at some theorems
• If the one pair of opposite sides If the one pair of opposite sides of a quadrilateral are both of a quadrilateral are both
congruent and parallel, then the congruent and parallel, then the quadrilateral is a parallelogram.quadrilateral is a parallelogram.
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Lets try a proofLets try a proof
• Given: ABDCDB, BDADBC, AC• Prove: ABCD is a parallelogram
A B
CD
Statement Reason
ABCD is a parallelogram
If opposite ’s ,
then parallaogram
•Given
ABD+CBDCDB+ADB
Addition
ABDCDB,
BDADBC
AC
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OK, here comes a problem.OK, here comes a problem.
A
B
C
D
3X
X+3.2
Y+2
3Y
ABCD is a parallelogram. Solve for X & Y.
3X = X+3.2 3Y = Y+2- 1X - 1X
2X = 3.2
2 2
X = 1.6
- 1Y - 1Y
2Y = 2
2 2Y = 1
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Just one more problemJust one more problem
A
B
C
D
m+9.1
4k-3.5
2.6k
m
ABCD is a parallelogram. Solve for m & k.
m+9.1 = 4k-3.5 m = 2.6k
substitution
2.6k+9.1 = 4k-3.5- 4k - 4k
-1.4k+9.1 = -3.5
- 9.1 - 9.1
-1.4k = -12.6
-1.4 -1.4
k = 9
m = 2.6(9)
m = 23.4
substitution
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