Turned in projects and completed reflection on project work. Learned about exterior angle theorem.
Notes from board
Homework
p. 185 #17-23 [CO-C10a]
Resources
algebraic examples of exterior angle theorem: link
Warm up was error analysis on using the exterior angle theorem. Went over homework, then reviewed classifications of triangles by both angles and sides (acute, right, obtuse, scalene, isosceles, equilateral). Constructed an isosceles triangle using compass and straight edge, went over vocabulary regarding isosceles triangles (base, base angles, vertex, legs) and constructed an angle bisector of the vertex angle. Then conjectured and proved the Isosceles Triangle Theorem, which opened up new avenues for angle chase problems, which we did to close out class.
Notes from board
Homework
p. 189 #5-8, 11-19 [CO-C10a]
Resources
isosceles triangle theorem proof: link
some algebraic examples: link
Warm up was another angle chase, this time involving parallels and isosceles triangles. Went over homework and discussed polygons, multi-sided figures which include triangles and quadrilaterals and beyond. Then developed the polygon angle sum formula by observing the pattern that there are always 2 fewer non-overlapping triangles than there are sides in a figure. This was then applied further to finding the individual angle measures of regular polygons. Then returned discussion to triangles and constructed the circumcenter and incenter of 2 different triangles by means of paper folding.
Notes from board
Homework
this handout (link)
assessment Monday: covers exterior angle theorem and isosceles triangle properties
Resources
forthcoming