In this lesson, students partition segments in given ratios. They begin by calculating midpoints, then attempt more difficult ratios in the subsequent activities. They’re introduced to a weighted average and asked to connect weighted averages to segment partitioning. Finally, they link segment partitioning to concepts of similarity transformations from earlier units. In each case, students are presented with a problem with little direction and expected to make sense of the problem and find a strategy on their own (MP1).
Lesson overview
 15.1 Warmup: Part Way: Points (5 minutes)

15.2 Activity: Part Way: Segment (15 minutes)
 Includes "Are you Ready for More?" extension problem
 15.3 Activity: Part Way: Quadrilateral (15 minutes)
 Lesson Synthesis
 15.4 Cooldown: Part Way: Triangle (5 minutes)
Learning goals:
 Calculate the coordinates of a point on a line segment that partitions the segment in a given ratio.
Learning goals (student facing):
 Let’s split segments using averages and ratios.
Learning targets (student facing):
 I can calculate the coordinates of a point on a line segment that partitions the segment in a given ratio.
Standards:
 This lesson builds on the standard: CCSS.HSGSRT.A.2MS.GSRT.2MO.G.SRT.A.2
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