Classifying Triangles Worksheet - Identify triangle types based on angles and side lengths.

Let’s go step by step to classify each triangle as right, scalene, isosceles, or equilateral.

We’ll use these definitions:

- Right triangle: Has one 90° angle (marked with a square corner).
- Scalene triangle: All sides are different lengths (no tick marks, or all sides have different markings).
- Isosceles triangle: At least two sides are equal (marked with same number of ticks).
- Equilateral triangle: All three sides are equal (all sides marked with same ticks — usually one tick per side).

Note: A triangle can be both right AND isosceles if it has a right angle and two equal sides. But in this worksheet, we’re asked to name *each* triangle using only ONE term from the list: right, scalene, isosceles, or equilateral. So we pick the most specific or obvious classification based on markings.

Let’s analyze each one:

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Triangle 1: Two sides have one tick mark → those two sides are equal → isosceles

Triangle 2: Has a right-angle symbol (square) → right

Triangle 3: All three sides have one tick mark → all sides equal → equilateral

Wait — actually, looking again: Triangle 3 has ticks on all three sides? Let me check carefully.

Actually, in Triangle 3: left side has one tick, bottom side has one tick, right side has one tick → yes, all three sides marked → equilateral

But wait — sometimes worksheets use different numbers of ticks for different pairs. In Triangle 3, all sides have exactly one tick → so equilateral.

Hold on — let me double-check standard notation:

- One tick = side length A
- Two ticks = side length B
- Three ticks = side length C

If all sides have same number of ticks → equilateral.

In Triangle 3: all sides have one tick → equilateral ✔

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Triangle 4: No tick marks, no right angle → assume all sides different → scalene

Triangle 5: Two sides have one tick → those two are equal → isosceles

Triangle 6: Has right-angle symbol → right

Triangle 7: Has right-angle symbol → right

Triangle 8: Two sides have one tick → isosceles

Triangle 9: Two sides have one tick → isosceles

Wait — Triangle 9: bottom side has one tick, right side has one tick → yes, two sides equal → isosceles

Triangle 10: All three sides have one tick → equilateral

Triangle 11: No ticks, no right angle → scalene

Triangle 12: Two sides have one tick → isosceles

Wait — let me recheck Triangle 12: left side has one tick, bottom side has one tick → yes, two sides equal → isosceles

Now, let’s list them all clearly:

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

Double-checking Triangle 3 and 10: both have all three sides marked with one tick → equilateral ✔️

Triangle 4 and 11: no markings, no right angles → scalene ✔️

Triangles with right angle: 2, 6, 7 → right ✔️

Others with two matching ticks: 1, 5, 8, 9, 12 → isosceles ✔️

All good.

Final Answer:
1. isosceles
2. right
3. equilateral
4. scalene
5. isosceles
6. right
7. right
8. isosceles
9. isosceles
10. equilateral
11. scalene
12. isosceles