1. Assumptions and Figures 3-B How do you determine what can and cannot be assumed from figures? How do you determine what can and cannot be assumed from pictures?

2. What can you assume?

8. To Assume or Not to Assume… In the figure, do you think you would be justified in assuming that: B, C, and E are collinear? BE ll GD? D A B C E F G

9. Make a List… Make a list of rules about what you think you can and cannot assume. A B C E F G

10. What can and cannot be assumed You May Assume:You May Not Assume (unless marked): Things that look straight are straight. Exact measurements and relative sizes of figures. Points shown on a line are collinear. Unless planes are drawn, all points shown are coplanar. Parallel or perpendicular lines. Relative position of points are accurate. Congruence

11. To Assume or Not to Assume… Point S is between R and T. Points R,S, and T are collinear. Point S is the midpoint of RT. VY<TY RSTV W Y Z

12. Try It Draw and mark one figure that shows all of the following relationships. On line m, B is the midpoint of AC. Line n ll m

13. How do you determine what can and cannot be assumed from figures? You May Assume:You May Not Assume (unless marked): Things that look straight are straight. Exact measurements and relative sizes of figures. Points shown on a line are collinear. Unless planes are drawn, all points shown are coplanar. Parallel or perpendicular lines. Relative position of points are accurate. Congruence

14. Assignment 3-3B Page 199, 1-4, 6-12, 17-21 Julian Beever is an English artist who's famous for his art on the pavements of England, France, Germany, USA, Australia and Belgium.