By third grade, students move beyond just naming shapes to actually understanding what makes each shape unique. What defines a triangle isn’t just that it looks like one — it’s that it has exactly three sides and three vertices. This is the kind of precise mathematical thinking that shows up on the STAAR and other grade-level assessments.
The worksheet below covers 2D shape attributes at the Grade 3 level: identifying shapes by their properties, counting sides and vertices, comparing shapes, and reasoning about categories. Answers are included at the end.
Key Vocabulary to Know
- Side: A straight line that forms part of a shape’s boundary
- Vertex (plural: vertices): A point where two sides meet (a corner)
- Polygon: A closed shape with straight sides
- Quadrilateral: A polygon with 4 sides and 4 vertices
- Right angle: An angle that forms a perfect square corner (90°)
2D Shapes Reference Chart
| Shape | Number of Sides | Number of Vertices | Notes |
|---|---|---|---|
| Triangle | 3 | 3 | Can be equilateral, isosceles, or scalene |
| Quadrilateral | 4 | 4 | Includes squares, rectangles, rhombuses, trapezoids |
| Rectangle | 4 | 4 | All 4 angles are right angles |
| Square | 4 | 4 | All sides equal, all angles right angles; a special rectangle |
| Pentagon | 5 | 5 | Regular pentagon has all equal sides |
| Hexagon | 6 | 6 | Regular hexagon looks like a honeycomb cell |
Practice Worksheet: 2D Shapes and Their Attributes
Part A: Fill in the Blanks
1. A triangle has _______ sides and _______ vertices.
2. A hexagon has _______ sides and _______ vertices.
3. A shape with 4 sides and 4 right angles where all sides are the same length is called a _______.
4. A rectangle has _______ right angles.
5. A pentagon has _______ more side(s) than a triangle.
Part B: True or False
6. A square is a type of rectangle. _______
7. All quadrilaterals have exactly 4 vertices. _______
8. A triangle can have a right angle. _______
9. A hexagon has fewer sides than a pentagon. _______
10. Every rectangle has 4 sides of equal length. _______
Part C: Short Answer
11. Maria draws a closed shape with exactly 5 straight sides. What is the name of her shape? How many vertices does it have?
12. James says that a square and a rectangle are completely different shapes. Is he correct? Explain your thinking.
13. Sort these shapes into two groups: triangle, square, pentagon, rectangle, hexagon.
Group 1: shapes with fewer than 5 sides.
Group 2: shapes with 5 or more sides.
14. A shape has 4 sides. Two of the sides are 6 cm long and two of the sides are 3 cm long. All angles are right angles. What shape is it? What is its perimeter?
15. Draw and label two different quadrilaterals that are NOT squares or rectangles. Name each one and describe one property that makes it different from a rectangle.
Answer Key
Part A
- 3 sides, 3 vertices
- 6 sides, 6 vertices
- Square
- 4 right angles
- 2 more sides (pentagon has 5, triangle has 3)
Part B
- True. A square is a special rectangle where all four sides are equal.
- True. All quadrilaterals have exactly 4 sides and 4 vertices.
- True. A right triangle has exactly one 90° angle.
- False. A hexagon has 6 sides; a pentagon has 5. A hexagon has more sides.
- False. A rectangle has 4 right angles and opposite sides that are equal, but not necessarily all four sides equal. Only a square has all four sides equal.
Part C
- The shape is a pentagon. It has 5 vertices.
- James is not entirely correct. A square is a special type of rectangle — one where all four sides are the same length. Every square is a rectangle, but not every rectangle is a square.
- Group 1 (fewer than 5 sides): triangle (3), square (4), rectangle (4). Group 2 (5 or more sides): pentagon (5), hexagon (6).
- The shape is a rectangle. Perimeter = 6 + 3 + 6 + 3 = 18 cm.
- Accept any two of these: rhombus (4 equal sides but angles are not right angles), trapezoid (exactly one pair of parallel sides), parallelogram (opposite sides parallel and equal, but angles are not right angles). Students should correctly identify a defining property.
Next Steps
Shape attributes lead directly into area, perimeter, and geometry classifications in the upper elementary grades. Once students are solid on sides and vertices, the next natural progression is classifying triangles (by side length and angle type) and understanding the hierarchy of quadrilaterals more deeply.
If you’re preparing for a Texas state assessment, the ViewMath Grade 3 STAAR series includes geometry questions at exactly this level — along with all other Grade 3 TEKS topics — in a STAAR-style format. Browse the full collection at viewmath.com/books/grade-3-math/grade-3-math-texas-staar-teks/.
