Angles in triangles (age 6+)
Distinguish defining attributes of shapes (e.g. triangles are closed and three-sided) from non-defining attributes (e.g. colour, orientation, overall size)
What a learner can do afterwards
- Build and draw shapes that possess defining attributes
- Identify that a shape remains a triangle regardless of its size, colour, or orientation
- Explain why a given shape is or is not a particular type based on its defining properties
The lesson
Every triangle has 3 straight sides and 3 corners. That is what makes it a triangle. It does not matter what color it is, how big it is, or which way it is turned.
Mia draws a tiny green triangle on her paper. Then she draws a huge yellow triangle next to it. They look very different, but both have 3 straight sides and 3 corners. So both are triangles.
To check if a shape is a triangle, do not look at the color or the size. Count the straight sides. If there are 3 sides and 3 corners, it is a triangle.
A triangle is a triangle because of its 3 sides and 3 corners, never because of its color, size, or direction.
Watch it
Where it sits
Learn first
This opens up
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.