Post on 18-Dec-2015
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Placing Figures on Coordinate Plane
1. Use the origin for vertex or center of figure.
2. Place at least one side on an axis.
3. Keep the figure within the first quadrant if possible.
4. Use coordinates that make computations as simple as possible.
"Nothing is ever achieved without enthusiasm." Ralph Waldo Emerson
Put these steps into your notes for today’s class
Mrs. Motlow Classroom Procedures
Obtaining Help: C3B4ME
1. If you need help, ask a classmate.
2. If not helped, ask another classmate.
3. If still not helped, ask the 3rd and final
classmate.
4. If still in need of help, raise your hand.
5. I will come to your desk to provide assistance or ask you to come to my desk.
If it is a common question, let me know so we can share the
answer with the class.
6. After being helped, quietly return to your
seat.
You are responsible
for helping other
classmates when
asked!
Page 297 8 – 30 Even8. Translation or reflection
10. Rotation
12. reflection, rotation or translation
14. Reflection
16. Translation
18. ABC is translation
20. XYZ is a rotation
22. Translation and rotation
24. Rotation
26. Translation
28. Vertical, A, H, I, M, O, T, U, V, W, X, Y
Horizontal B, C, D, E, H, I, K, O, X
Chapter 4.8 Triangles and Coordinate Proof
Objective: Write coordinate proofs and be able to position and label triangle for coordinate proofs.
CLE 3108.3.1 Use analytic geometry tools to explore geometric problems involving parallel and perpendicular lines, circles, and special points of polygons.
CLE 3108.4.3 Develop an understanding of the tools of logic and proof, including aspects of formal logic as well as construction of proofs.
Spi.3.2,Use coordinate geometry to prove characteristics of polygonal figures.
Placing Figures on Coordinate Plane
1. Use the origin for vertex or center of figure.
2. Place at least one side on an axis.
3. Keep the figure within the first quadrant if possible.
4. Use coordinates that make computations as simple as possible.
"Nothing is ever achieved without enthusiasm." Ralph Waldo Emerson
Practice
1. Position and label and isosceles triangle JKL on a coordinate plane so that the base JK is a units long.
2. Use the origin as vertex J
3. Place the base of the triangle along the positive x axis
4. Position the triangle in the first quadrant.
5. Place vertex K at position (a, 0) to make JK a units long
6. Since JKL is isosceles, position point L ½ way between point J and K or at x coordinate a/2. Height is unknown, label b.
J K(0, 0)
(0, a)
L (a/2, b)
Find the missing coordinates
F
(?, ?)
E(0, a)
G (?, ?)
• Name the missing coordinates of the Isosceles right triangle EFG.
• Given E (0, a)• F (?, ?)
• (0,0)• G (?, ?)
• (a, 0), because isosceles triangle
Find the missing coordinates
Q
(?, ?)
S(?, ?)
R (c, 0)
• Name the missing coordinates of the Isosceles right triangle QRS.
• Given R (c, 0)• Q (?, ?)
• (0,0)• S (?, ?)
• (c, c), because isosceles triangle
Coordinate Proof• Write a coordinate proof to prove that the measure of the
segment that joins the vertex of the right angle in a right triangle to the midpoint of the hypotenuse is one half the measure of the hypotenuse.
A
(0, 0)
B(0, 2b)
C
(2c, 0)
P(?, ?)
• Given: Right ABC, P midpoint BC• Prove: AP = ½ BC
Midpoint