Isosceles, Equilateral, and Scalene Triangles worksheet | Live ... - Free Printable

Let's solve this step by step.

We are asked to classify each triangle as Equilateral, Isosceles, or Scalene based on the lengths of their sides. The markings (small lines or ticks) on the sides indicate which sides are equal in length:

- Equilateral: All three sides are equal (all sides have the same tick marks).
- Isosceles: Two sides are equal (two sides have the same tick marks).
- Scalene: All sides are different (no sides have the same tick marks).

Now, let’s go through each triangle:

---

1) Triangle 1:
- All three sides have a single tick mark (same marking).
→ All sides equal
✔ Equilateral

2) Triangle 2:
- Two sides have one tick mark, the third side has no tick.
→ Two sides equal
✔ Isosceles

3) Triangle 3:
- No tick marks on any side → all sides different
✔ Scalene

4) Triangle 4:
- No tick marks → all sides different
✔ Scalene

5) Triangle 5:
- Two sides have tick marks, the third does not
→ Two sides equal
✔ Isosceles

6) Triangle 6:
- Two sides have tick marks, the third does not
→ Two sides equal
✔ Isosceles

7) Triangle 7:
- Two sides have tick marks, the third does not
→ Two sides equal
✔ Isosceles

8) Triangle 8:
- No tick marks → all sides different
✔ Scalene

9) Triangle 9:
- All three sides have tick marks (one each) → all sides equal
✔ Equilateral

10) Triangle 10:
- This is not a triangle — it looks like a quadrilateral or irregular shape with four sides.
✘ Not a triangle → likely an error or trick question. But since it's labeled as triangle, maybe it's drawn incorrectly.
However, if we assume it's meant to be a triangle, but clearly has 4 sides, it's invalid.
But looking closely: it might be a distorted triangle? Actually, it appears to have four sides — so not a triangle.
But since the task says "triangles", and this one is clearly not, perhaps it's a mistake.
However, assuming it's a triangle and we're to judge by sides, but it has no tick marks — and seems to have 3 sides? Let’s recheck.

Wait — actually, upon closer inspection, triangle 10 has three sides, but it's drawn oddly. It has no tick marks. So unless there’s a hidden marking, we assume all sides are different.
→ No tick marks → all sides different
✔ Scalene

But note: if it's a valid triangle, then yes — scalene.

11) Triangle 11:
- Two sides have tick marks, the third does not
→ Two sides equal
✔ Isosceles

12) Triangle 12:
- All three sides have tick marks (one each) → all sides equal
✔ Equilateral

---

Final Answers:

1) Equilateral
2) Isosceles
3) Scalene
4) Scalene
5) Isosceles
6) Isosceles
7) Isosceles
8) Scalene
9) Equilateral
10) Scalene
11) Isosceles
12) Equilateral

---

Summary of Classifications:

- Equilateral: 1, 9, 12
- Isosceles: 2, 5, 6, 7, 11
- Scalene: 3, 4, 8, 10

> Note: Triangle 10 might be visually confusing due to its shape, but since it has three sides and no tick marks indicating equality, it's classified as scalene. If it were truly a quadrilateral, it wouldn't be a triangle — but in context, it's treated as a triangle.

✔ Final Answer Labels:
1) Equilateral
2) Isosceles
3) Scalene
4) Scalene
5) Isosceles
6) Isosceles
7) Isosceles
8) Scalene
9) Equilateral
10) Scalene
11) Isosceles
12) Equilateral