1. Let’s Review: Mrs. Horne 4 th Grade Niwot Elementary Geometry

2. It’s all about VOCABULARY! Let’s get started. It’s important to recognize & name geometric shapes.

3. Here are some common shapes you may already recognize. Square, Rectangle, Triangle, Circle. Got it!

4. But that’s jumping ahead. Let’s start with the building blocks of shapes. In everyday language, we call these lines.

5. In geometry, a line has no beginning and no end. Here’s an example of a line Lines extend infinitely in BOTH DIRECTIONS.

6. A ray has a starting point and then extends infinitely in one direction. Later!

7. A line segment has a starting point and an end point. You use the points to name the line segment. This is line segment AB, and THIS is line segment A-present-for-mE!

8. When lines stay the same distance apart and never cross or intersect, we call them parallel lines. They can be lines, rays, line segments, or any combination of these, AS LONG AS THEY NEVER INTERSECT

11. When lines intersect they form angles. Here are 3 common types of angles. Acute Right Obtuse or 90 Degree

12. When lines intersect to form right or 90 degree angles, we call them perpendicular lines. Looks like the “right” angle to me!

13. Here are some more examples of perpendicular lines.

14. Shapes can be created with line segments. A polygon is any shape that has 3 or more sides. Aarrg! I’ve lost me parrot, but there be some polly-gones. Shhh! I’m hiding!

15. A polygon with 3 sides is called a triangle. I’ll never count all those!

16. There are several types of triangles. That’s more like it.

17. 4-sided shapes are called quadrilaterals. “Quad” means 4 “Lateral” means side, so quadrilaterals are shapes with 4 sides. Makes sense.

18. Quadrilaterals can be identified further based on attributes like the length of each side, the measurement of the angles, and whether or not the sides are parallel. Bring ‘em on! I’ll attack them like a lasagna. They don’t stand a chance!

19. Here’s the first shape 4 sides? Check! Opposite sides parallel? Check! 4 right angles? Check! All sides the same length? Check! This is so easy! It’s a SQUARE.

20. Here are some more examples of squares.

23. Here’s the next shape 4 sides? Check! Opposite sides parallel? Check! 4 right angles? Check! All sides the same length? NO!! But opposite sides are equal It’s gotta’ be a RECTANGLE!

24. Here are some more examples of rectangles.

27. Try this one 4 sides? Check! Opposite sides parallel? Check! 4 right angles? Not Always But the opposite angles are equal All sides the same length? Not always But opposite sides are equal It must be a PARALLELOGRAM.

28. Here are some more examples of parallelograms.

29. Here’s another one 4 sides? Check! Opposite sides parallel? Check! 4 right angles? NO!! (there’s 1 exception) But the opposite angles are equal All sides the same length? Check! This can only mean one thing. This is a RHOMBUS (which, by the way, is a special form of parallelogram).

30. Here are some more examples of rhombi.

31. 4 sides? Check! 4 right angles? NO!! But 2 of the angles could be All sides the same length? NO!! But the opposite sides that aren’t parallel could be It’s gotta’ be a TRAPEZOID. Here’s the last one Opposite sides parallel? NO!! ONLY 1 pair of opposite sides is parallel

32. Here are some more examples of trapezoids.

33. It can get confusing, but this chart can help

34. So a SQUARE is just a special rhombus with 90 degree angles. It’s also a parallelogram because each pair of opposite sides is parallel. And it’s a type of rectangle because it has 4 right angles and the opposite sides are congruent (that’s geometry talk for exactly the same size and shape.)

35. Thanks a lot, Odie. I forgot to tell you about kites. Why don’t you make like a kite and fly away?

36. That’s all, folks! I hope you liked reviewing geometry vocabulary!