ElementarythirdquarterCongruent Polygons.ppt
- 2. Naming & Comparing Polygons ♥ List vertices in order, either clockwise or counterclockwise. ♥ When comparing 2 polygons, begin at corresponding vertices; name the vertices in order and; go in the same direction. ♥ By doing this you can identify corresponding parts. A D C B E DCBAE P I J K H IJKPH D corresponds to I AE corresponds to PH
- 3. Name corresponding parts • Name all the angles that correspond: A D C B E P I J K H D corresponds to I C corresponds to J B corresponds to K A corresponds to P E corresponds to H DCBAE IJKPH • Name all the segments that correspond: DC corresponds to IJ CB corresponds to JK BA corresponds to KP AE corresponds to PH ED corresponds to HI How many corresponding angles are there? How many corresponding sides are there? 5 5
- 4. • How many ways can you name pentagon DCBAE? A D C B E 10 Do it. DCBAE CBAED BAEDC AEDCB EDCBA Pick a vertex and go clockwise Pick a vertex and go counterclockwise DEABC CDEAB BCDEA ABCDE EABCD
- 5. Polygon Congruence Postulate • If each pair of corresponding angles is congruent, and each pair of corresponding sides is congruent, then the two polygons are congruent.
- 6. Congruence Statements • Given: These polygons are congruent. • Remember, if they are congruent, they are EXACTLY the same. • That means that all of the corresponding angles are congruent and all of the corresponding sides are congruent. • DO NOT say that ‘all the sides are congruent” and “all the angles are congruent”, because they are not. G H F E C D B A ABCD = EFGH ~
- 7. Prove: ΔLXM = ΔYXM ~ X Y M L Statements Reasons XY = XL Given LM = YM Given XM = XM Reflexive Property LXM = YXM Given L = Y Given XMY = SML Right angles ΔLXM = ΔYXM Polygon Congruence Postulate ~ ~ ~ ~ ~ ~ ~