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Grade 5 Math · World 9: Polygon Palace · Level 86
Triangle Properties
Compare triangles by angles, sides, and symmetry.
Warm-up, learn, try it together, practice, then a quick check. About 15 minutes.
What children learn in Level 86
- Triangles have two kinds of names. By angles, a triangle is right, acute, or obtuse.
- By sides, equilateral has 3 equal sides, isosceles has at least 2, and scalene has none. So an equilateral triangle is isosceles too.
- Symmetry connects to sides. Equilateral has 3 lines of symmetry, isosceles has 1, and scalene has none.
- One triangle gets both kinds of name. A triangle can be a right isosceles triangle.
Georgia's K-12 Mathematics Standards:
- 5.GSR.8.1 — Classify, compare, and contrast polygons based on properties.