Geometry · Lines, Segments, and Rays

Turn three points on a line into an equation

Use the Segment Addition Postulate and the definition of midpoint to solve for unknown lengths — sourced from Acing SAT Math, Chapter 16 §16-1.

Segment Addition PostulateMidpointProportion

Part 1 · Segment Addition Postulate

A road trip with three stops

You drive from Houston (A) to Austin (B) — 125 miles — then keep driving from Austin (B) to Dallas (C) — 85 miles — along a straight highway. How do you find the total distance from Houston to Dallas?

Add the two distances togetherSubtract the Austin–Dallas leg from the Houston–Austin legMultiply the distance from Houston to Austin by the distance from Austin to DallasOnly use the distance from Austin to Dallas, since that's the last leg