In this lesson our instructor talks about parallel lines and proportional parts. First she talks about triangle proportionality and its converse. Then she discusses triangle midsegment and parallel lines and transversal. Four extra example videos round up this lesson.
If a line is parallel to one side of a triangle and intersects the other two sides in two distinct points, then it separates these sides into segments
Triangle Proportionality Converse: If a line intersects two sides of a triangle and separates the sides into corresponding segments of proportional lengths, then the line is parallel to the third side
Triangle Mid-segment: A segment whose endpoints are the midpoints of two sides of a triangle is parallel to the third side of the triangle, and its length is one-half the length of the third side
If three or more parallel lines intersect two transversals, then they cut off the transversals proportionally
If three or more parallel lines cut off congruent segments on one transversal, then they cut off congruent segments one very transversal
Parallel Lines and Proportional Parts
Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.