4/26 Half Day

Do Now 4/26 EQ: What is the triangle proportionality theorem? 1. What is the length of side BC? 2. If you could travel anywhere in the world, where would you go and why? EQ: What is the triangle proportionality theorem?

Agenda Do Now Good Things! Unit 4 Review Notes: Practice Problems Triangle Proportionality Theorem Triangle Bisector Theorem Practice Problems

Good things

Triangle proportionality theorem In this figure *the arrows in the middle tell us that these lines are parallel According to this theorem, Left Short / Left Long = Right Short / Right Long

Triangle Proportionality theorem If a line parallel to one side of a triangle intersects the other two sides of the triangle, then the parallel line divides the other two sides proportionally How is this different from the midsegment theorem?

Triangle Proportionality Theorem 1. Are lines DE & AC parallel? 2. Write a proportion to find the missing side

Working Backwards If the parts are proportional, this means that the line crossing the triangle MUST be parallel. Is DE parallel to AC??? Are these ratios equal? NO Line DE is not parallel to AC because of the Triangle Proportionality Theorem

Partner Practice Find the length of CD Is AB parallel to EC?

Triangle Angle Bisector Theorem A bisector is a line that cuts something in half If an angle of a triangle is bisected (cut in half), the bisector divides the opposite side of the triangle into two segments that are proportional to the other two sides of the triangle Bisector bottom parts of both triangles hypotenuse of both triangles

Group Practice Find the length of BD Find the lengths of CD & CB

Practice Problems Online worksheet