A triangle has 3 straight sides. That is what makes it a triangle.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
What does not matter
Its colour does not matter. Its size does not matter. Which way it points does not matter.
Turn a triangle upside down. It still has 3 sides. It is still a triangle.
Count the sides and the corners. Those are the parts that count.
Corner is where two sides meet.
Some things decide, some do not
Number of sides decides. Colour, size and which way up do not. Sorting those two lists is what naming a shape means.
Why it must work that way
If colour mattered, two people could disagree about a shape. Counting sides gives everyone the same answer.
Step 2: Try It Yourself
Turn it and resize it. Watch the name stay the same.
Triangle
Straight sides
3
Corners
3
A triangle has 3 straight sides.
Turning it does not change what it is.
Step 3: Watch an Example
One step at a time.
Watch Ana Check a Shape
Ana is shown a small red triangle pointing down.
- Step 1
She ignores the colour. Colour does not decide.
Step 4: Your Turn
Practice makes it stick.
Two Shapes
Problem 1 of 1
A big blue triangle and a small red one. Are both triangles?
Does It Matter?
1 of 3
How many sides does a triangle have?
2 of 3
Does turning a shape change what it is?
3 of 3
Which one decides the shape?
Step 5: Quick Check
Show what you know.
Question 1 of 2
How many corners does a triangle have?
Question 2 of 2
Is a tiny green triangle still a triangle?
What You Learned
- Sides and corners decide what a shape is.
- Colour, size, and turning do not decide.
- A triangle has 3 straight sides, always.