4.4.1 Prove Triangles congruent by SAS and HL
The included angle – the angle formed by two given sides of a triangle Example: Given AB and BC, the included angle is B A B C Included Angle Given Sides
The side lengths define a ratio ◦ This ratio is created by the end points and the distance formula ◦ Only one line can be drawn given a fixed included angle ◦ any triangle formed is congruent Fixed Included Angle Only one Segment can be drawn
SAS: Given two sides and the included angle of one triangle are congruent to two sides and the included angle of a second triangle, then the two triangles are congruent. A BC D Example: AC CA (Symmetric) CB AD (Given) ACB CAD (AIA) ACB CAD (SAS)
We have been working with triangles because they play a big role in other shapes Previous example (slide 4) was a parallelogram which we will study in chapter 8 after we finish triangles Other examples exist: Classify this Circumscribed (outside) figure; Prove using SAS this is a regular hexagon: A F B E D C
P. 243 3, 5, 7, 9, 12, 13, , 20, 21, 35