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Grade 5 Math · World 9: Polygon Palace · Level 90
Measure to Decide
Use angle and side measures to classify a shape.
Warm-up, learn, try it together, practice, then a quick check. About 15 minutes.
What children learn in Level 90
- Your eyes can fool you. A shape can look like a square and not be one. Rulers and protractors tell for sure.
- Here's a shape with all sides 5 centimeters. Its angles are 70, 110, 70, and 110 degrees. The sides are equal, but the angles aren't right angles. So it's a rhombus, not a square.
- For triangles, side lengths and the largest angle tell you everything. Sides of 4, 4, and 6 make an isosceles triangle.
- Try it with a grown-up. Find a real rectangle at home, and measure to prove that its opposite sides match.
Georgia's K-12 Mathematics Standards:
- 5.GSR.8.1 — Classify, compare, and contrast polygons based on properties.