Classifying Triangles Worksheet | Download Free Printables For Kids - Free Printable

To classify each triangle, we look at the lengths of its sides:

- Equilateral: All 3 sides are equal.
- Isosceles: Exactly 2 sides are equal.
- Scalene: All 3 sides are different.

We’ll go row by row and examine each triangle visually (since no measurements are given, we rely on visual comparison — which is standard for this type of worksheet).

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Row 1:

- 1a. Red triangle – looks like all sides are different → scalene
- 1b. Blue triangle – two sides appear equal (left and right), base shorter → isosceles
- 1c. Blue triangle – all sides clearly different lengths → scalene

Row 2:

- 2a. Green triangle – all sides different → scalene
- 2b. Red triangle – two long sides equal, base shorter → isosceles
- 2c. Green triangle – all sides different → scalene

Row 3:

- 3a. Blue triangle – two sides equal (the slanted ones), base different → isosceles
- 3b. Red triangle – all sides different → scalene
- 3c. Green triangle – all sides different → scalene

Row 4:

- 4a. Blue triangle – all sides different → scalene
- 4b. Green triangle – all sides different → scalene
- 4c. Red triangle – all sides different → scalene

Wait — let’s double-check a few that might be tricky.

Look again at 1b: The blue triangle in 1b — it’s drawn with two sides looking equal? Actually, upon closer inspection (imagining the angles), if two angles look equal, then two sides are equal. But in many such worksheets, unless it's obviously symmetric, they may intend scalene. However, 1b does look like an isosceles triangle — apex angle smaller, two legs same length.

Similarly, 2b is tall and narrow — definitely isosceles.

3a — the blue one pointing left — looks like two sides equal (top and bottom slant), base vertical — yes, isosceles.

Now, what about equilateral? None of these triangles have all three sides equal. In fact, none look even close to equilateral. So probably there are zero equilateral triangles here.

Let me list them again carefully:

1a: scalene
1b: isosceles (two sides equal)
1c: scalene

2a: scalene
2b: isosceles
2c: scalene

3a: isosceles
3b: scalene
3c: scalene

4a: scalene
4b: scalene
4c: scalene

That gives us:
- Isosceles: 1b, 2b, 3a → 3 triangles
- Scalene: all others → 9 triangles
- Equilateral: none

But wait — let’s check 3c again. The green triangle in 3c — could it be isosceles? It looks like the top side and right side might be similar? Hmm… actually, no — the left side is longer, bottom is medium, right is short — still scalene.

What about 4b? Green triangle — very skewed, all sides different — scalene.

So final count per cell:

1a: scalene
1b: isosceles
1c: scalene
2a: scalene
2b: isosceles
2c: scalene
3a: isosceles
3b: scalene
3c: scalene
4a: scalene
4b: scalene
4c: scalene

Yes, that seems consistent.

Final Answer:
1a: scalene
1b: isosceles
1c: scalene
2a: scalene
2b: isosceles
2c: scalene
3a: isosceles
3b: scalene
3c: scalene
4a: scalene
4b: scalene
4c: scalene