Virginia SOL 5.MG.3.d
The Standard
Compare and contrast the properties of triangles.
Virginia Standards of Learning for Mathematics · The student will classify and measure angles and triangles, and solve problems, including those in context.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students sort and name triangles using side lengths and angle types. They compare two triangles and explain shared and different properties using measurements or markings.
What Mastery Looks Like
- Students correctly label triangles as equilateral, isosceles, or scalene and as acute, right, or obtuse. They use side marks, lengths, and angle measures to explain how two triangles are alike and different.
Common Misconceptions
- Students may classify a triangle by how it looks instead of checking side lengths and angles. They may think turning a triangle changes its type. They may also give only one label, forgetting that a triangle can be classified by both sides and angles.
How to Assess It
- Ask students to draw an isosceles right triangle and a scalene right triangle. Have them write one similarity and one difference between the two.
Lesson moves
Ways to Teach It
Build triangles with cut straws, then measure sides and angles and place each model on a class sorting mat.
Compare an isosceles right triangle and an isosceles acute triangle: What stays the same, and what changes?
Play Triangle Sort: draw a card, classify its triangle by sides and angles, then justify both labels for one point.
Photograph roof trusses, bridge braces, or signs, then label each visible triangle by side lengths and angle types.
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Printable 5.MG.3.d Worksheet
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Related Standards
- 5.MG.3.b
Classify triangles as right, acute, or obtuse and equilateral, scalene, or isosceles and justify reasoning.
- 7.MG.3.a.iii
Compare and contrast properties of the following quadrilaterals: parallelogram, rectangle, square, rhombus, and trapezoid: lines of symmetry.
- 7.MG.3.a.i
Compare and contrast properties of the following quadrilaterals: parallelogram, rectangle, square, rhombus, and trapezoid: parallel/perpendicular sides and diag...
- 7.MG.3.a.ii
Compare and contrast properties of the following quadrilaterals: parallelogram, rectangle, square, rhombus, and trapezoid: congruence of angle measures, side, a...
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