HH.1 Identify parallel sides in quadrilaterals
What are parallel sides?
Parallel sides are two sides of a shape that are always the same distance apart and never meet, no matter how far they are extended.
- In a rectangle, both pairs of opposite sides are parallel.
- In a square, both pairs of opposite sides are parallel.
- In a trapezoid, only one pair of sides is parallel.
You can think of parallel sides like railroad tracks—no matter how far they go, they never cross each other.
How to identify parallel sides in quadrilaterals
To identify parallel sides, look for pairs of sides that run in the same direction and will never touch, even if extended with lines.
- Look at the opposite sides of the quadrilateral.
- Imagine extending the sides with a ruler or straight line.
- If the sides never cross, they are parallel.
Parallel sides usually “face” each other. Check both pairs of opposite sides in four-sided shapes.
Quadrilaterals with parallel sides
Different quadrilaterals have different numbers of parallel sides. Knowing this helps you name and classify them.
- Square: 2 pairs of parallel sides
- Rectangle: 2 pairs of parallel sides
- Parallelogram: 2 pairs of parallel sides
- Trapezoid: 1 pair of parallel sides
- Kite: 0 pairs of parallel sides
Quadrilaterals can be grouped by how many pairs of parallel sides they have. This is an important clue to identifying them correctly.
Using parallel sides to describe shapes
When describing quadrilaterals, use the number of parallel side pairs as part of their definition and classification.
- “A rectangle has 2 pairs of parallel sides.”
- “A trapezoid has exactly 1 pair of parallel sides.”
- “A kite does not have parallel sides.”
Describing quadrilaterals by their sides makes it easier to see the differences and similarities between shapes.