ALEX Resources

   View Standards     Standard(s): [MA2015] GEO (9-12) 10 :

10 ) Prove theorems about triangles. Theorems include measures of interior angles of a triangle sum to 180^o, base angles of isosceles triangles are congruent, the segment joining midpoints of two sides of a triangle is parallel to the third side and half the length, and the medians of a triangle meet at a point. [G-CO10]

[MA2015] GEO (9-12) 16 :

16 ) Use the properties of similarity transformations to establish the angle-angle (AA) criterion for two triangles to be similar. [G-SRT3]

[MA2015] GEO (9-12) 17 :

17 ) Prove theorems about triangles. Theorems include a line parallel to one side of a triangle divides the other two proportionally, and conversely; and the Pythagorean Theorem proved using triangle similarity. [G-SRT4]

[MA2019] GEO-19 (9-12) 32 :

32. Use coordinates to prove simple geometric theorems algebraically.

[MA2019] GEO-19 (9-12) 34 :

34. Use congruence and similarity criteria for triangles to solve problems in real-world contexts.

This math brainteaser challenges you to find a simple, elegant solution to a seemingly complex problem! Students will use geometry principles and their knowledge about triangles to solve this puzzle. Can you figure it out?

   View Standards     Standard(s): [MA2015] GEO (9-12) 16 :

16 ) Use the properties of similarity transformations to establish the angle-angle (AA) criterion for two triangles to be similar. [G-SRT3]

[MA2015] GEO (9-12) 17 :

17 ) Prove theorems about triangles. Theorems include a line parallel to one side of a triangle divides the other two proportionally, and conversely; and the Pythagorean Theorem proved using triangle similarity. [G-SRT4]

[MA2019] GEO-19 (9-12) 27 :

27. Given two figures, determine whether they are similar by identifying a similarity transformation (sequence of rigid motions and dilations) that maps one figure to the other.

[MA2019] GEO-19 (9-12) 34 :

34. Use congruence and similarity criteria for triangles to solve problems in real-world contexts.

[MA2019] GEO-19 (9-12) 36 :

36. Use geometric shapes, their measures, and their properties to model objects and use those models to solve problems.

Students learn what it means for two figures to be similar in general, and then focus on triangles and what criteria predict that two triangles will be similar. Length relationships within and between figures are studied closely and foreshadows work in Module 2, Topic D. The topic closes with a look at how similarity has been used in real-world application.