1 Press Ctrl-A ©G Dear2008 – Not to be sold/Free to use Rule 01 Stage 4 - Year 9

2 B A triangle B twice triangle A All sides of triangle B are twice as long as triangle A. They are similar 1 three sides three sides similar If the three sides of one triangle are proportional to the three sides of another triangle, the two triangles are similar.

A B Longest A Longest B 510 = Middle A Middle B 48 = Shortest A Shortest B 36 = 12 They are in proportion. They are similar 1

4 12 three sides three sides similar If the three sides of one triangle are proportional to the three sides of another triangle, the two triangles are similar A BC D EF ABDE = 36 = Label each triangle. BCEF = 48 = ACDF = 510 = 12  ΔABC ||| ΔDEF ABDE = BCEF = ACDF  (corresponding sides in proportion) 12