17.1.1 A Look Back at Ratio and Proportion
Core ideaWhich cup of sugar water is sweeter comes down to the ratio of sugar parts to water parts, a:b.
Module goal. Picking up the parallel lines and congruence from quadrilaterals, we carry the idea of a 'ratio' between numbers over to the lengths of line segments, building the language of proportional segments that lays the foundation for everything about similarity to come.