Parallel and Intersecting Lines
What are parallel lines? Give an example.
Parallel lines are straight lines that never meet.
Example: Railway tracks—they run side by side but never touch.
What is a vertical line?
A vertical line goes straight up and down.
What is an edge of a cube?
An edge is a straight line where two faces of a cube meet. It's like the "side" of the cube.
Name a quadrilateral with 4 equal sides.
Square or rhombus.
Define a rectangle.
A rectangle is a flat 2D shape with 4 sides and 4 right angles (90°).
How do intersecting lines look?
Intersecting lines are two straight lines that cross each other at one point, called the point of intersection.
What is a horizontal line?
A horizontal line is a straight line that runs left to right (or right to left).
Describe a face of a rectangular prism.
A face is one of the flat surfaces on a rectangular prism, either a square or rectangle (a box shape).
What is a trapezoid?
A trapezoid is a 4-sided flat shape (quadrilateral) with exactly one pair of parallel sides.
List similarities between a square and a rectangle.
Both quadrilaterals
Opposite sides parallel + equal
All angles = 90°
Give an example of parallel edges in a 3-D object.
Rectangular Prism:
- Edges: The top front edge and bottom front edge (B) run parallel to each other.
Cube:
- All 12 edges are parallel to at least one other edge (e.g., all vertical edges are parallel).
How can you tell if lines are perpendicular?
They cross at a square corner (90°).
- Example: The letter "L" or a + sign.
Draw a cube and mark all the edges with bold lines. How many edges does it have in total?
Top face: 4 edges
Bottom face: 4 edges
Vertical sides: 4 edges
12 edges total!
List two types of quadrilaterals with parallel sides.
Rectangle, parallelogram, square, rhombus.
Parallel sides never meet, no matter how far they extend!
What makes a rhombus different from a square?
- A square is a special rhombus where all angles are 90°.
- A rhombus is a "tilted square" (unless its angles are 90°).
Look around your classroom. Find two examples of objects or shapes that show intersecting lines. Draw one of them and mark the point where the lines cross.
Show your work.
Where would you find vertical lines in your home?
Give 5 examples.
Describe how to find horizontal faces on a cube.
Look for the "top" and "bottom" of the cube (like the lid and base of a box).
Check if they’re flat and level (parallel to the ground).
Count them: Every cube has 2 horizontal faces—one on top, one on the bottom.
Sort these shapes based on attributes: square, rectangle, parallelogram.
1. Square
- All sides equal
- All angles = 90°
2. Rectangle
- Opposite sides equal
- All angles = 90°
3. Parallelogram
- Opposite sides equal and parallel
- Opposite angles equal (any angle)
Explain how you know a shape is a quadrilateral.
1. Count the Sides:
- A quadrilateral always has 4 straight sides.
2. Check the Corners:
- It must have 4 angles (corners) where the sides meet.
3. Closed Shape:
- The sides must connect end-to-end with no gaps.
Create a sketch showing parallel and intersecting lines.
Show and label your work.
As a team, demonstrate a vertical and a horizontal line with your body.
Show your teamwork.
Work as a team to identify edges and faces on a 3-D object you see.
Show your teamwork.
Name a real-life example of a rhombus.
♦️ Playing cards’ diamond suit.
🔶 A baseball diamond (the infield area) is a perfect rhombus!
Work as a team to draw a diagram (like a family tree) to show how these shapes are related: square, rectangle, rhombus, parallelogram, kite, and trapezoid. Use arrows or labels to explain which shapes are special types of others.
Show and label your work and demonstrate teamwork!