All angles 90°
Square: A quadrilateral with 4 equal sides and 4 right angles (90°)
- Count the number of sides (must be 4 for a quadrilateral)
- Check if all 4 sides are equal in length
- Verify that all 4 angles are right angles (90°)
This shape has 4 sides, so it's a quadrilateral.
All 4 sides are equal in length.
All 4 angles are right angles (90°).
Since it has 4 equal sides and 4 right angles, this is a square.
This is a square because it has 4 equal sides and 4 right angles.
• Quadrilateral: Must have exactly 4 sides
• Square definition: 4 equal sides + 4 right angles
• Angle measurement: Right angles measure 90°
All angles 90°
Rectangle: A quadrilateral with opposite sides equal and 4 right angles (90°)
This shape has 4 sides, so it's a quadrilateral.
Opposite sides are equal in length (long sides equal, short sides equal).
All 4 angles are right angles (90°).
Since it has opposite sides equal and 4 right angles, this is a rectangle.
This is a rectangle because it has opposite sides equal and 4 right angles.
• Rectangle definition: Opposite sides equal + 4 right angles
• Parallel sides: Opposite sides are parallel
• Angle property: All angles are 90°
Opposite angles equal
Rhombus: A quadrilateral with 4 equal sides, but not necessarily right angles
This shape has 4 sides, so it's a quadrilateral.
All 4 sides are equal in length.
The angles are not 90°, but opposite angles are equal.
Since it has 4 equal sides but not 4 right angles, this is a rhombus.
This is a rhombus because it has 4 equal sides but not 4 right angles.
• Rhombus definition: 4 equal sides
• Angle property: Opposite angles are equal
• Diagonal property: Diagonals bisect each other at right angles
- Count sides: Must have 4 sides to be a quadrilateral
- Measure sides: Check for equal sides
- Measure angles: Look for right angles or equal angles
- Check for parallelism: Identify parallel sides
- Classify: Match properties to specific quadrilateral type
Non-parallel sides
Trapezoid: A quadrilateral with exactly one pair of parallel sides
This shape has 4 sides, so it's a quadrilateral.
Only one pair of opposite sides is parallel (the top and bottom).
The other two sides are not parallel to each other.
Since it has exactly one pair of parallel sides, this is a trapezoid.
This is a trapezoid because it has exactly one pair of parallel sides.
• Trapezoid definition: Exactly one pair of parallel sides
• Parallel lines: Lines that never intersect
• Non-parallel sides: May or may not be equal in length
Perpendicular diagonals
Kite: A quadrilateral with two pairs of adjacent sides that are equal
This shape has 4 sides, so it's a quadrilateral.
Two pairs of adjacent sides are equal in length.
There are no parallel sides in this shape.
The diagonals intersect at right angles (perpendicular).
Since it has two pairs of adjacent equal sides, this is a kite.
This is a kite because it has two pairs of adjacent equal sides.
• Kite definition: Two pairs of adjacent equal sides
• No parallel sides: Usually no parallel sides
• Diagonal property: Diagonals are perpendicular
Quadrilateral: A polygon with 4 sides and 4 vertices
Parallelogram: Quadrilateral with both pairs of opposite sides parallel
Special quadrilaterals: Squares, rectangles, rhombuses, trapezoids, kites
- Count sides: Verify it has exactly 4 sides
- Measure sides: Determine if sides are equal or different
- Measure angles: Check for right angles or equal angles
- Check parallelism: Identify parallel sides
- Look for symmetry: Check for lines of symmetry
- Classify: Match to specific quadrilateral type
• Square: 4 equal sides + 4 right angles + 4 lines of symmetry
• Rectangle: Opposite sides equal + 4 right angles + 2 lines of symmetry
• Rhombus: 4 equal sides + opposite angles equal + 2 lines of symmetry
• Parallelogram: Opposite sides equal and parallel + opposite angles equal
• Trapezoid: Exactly one pair of parallel sides
• Kite: Two pairs of adjacent equal sides + perpendicular diagonals