Students measure angles in three triangles using a protractor and calculate the sum of angles in each.

Let’s work through this step by step.

We are given three triangles, and we’re told to:
1. Measure each angle in the triangle using a protractor (but since we can’t physically measure here, we’ll use geometry rules).
2. Add up the angles in each triangle.
3. Write the total in the middle of the triangle.
4. Notice what happens — there’s a pattern!

But wait — we don’t have actual measurements from a protractor. However, we *can* figure out the angles based on the shapes shown.

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Triangle 1:
This is a right triangle — you can see the little square at one corner, which means that angle is 90°.

Looking at the shape, it looks like an isosceles right triangle? Wait — no, actually, looking closely, the two legs are not equal. But let’s think differently.

Actually, in any triangle, the sum of interior angles is always 180° — that’s a rule we can rely on.

So even if we don’t measure with a protractor, we know:

→ For Triangle 1: One angle is 90° (right angle). The other two must add up to 90°. From the drawing, they look like 45° and 45°? Or maybe not? Let’s check the shape again.

Wait — actually, looking at Triangle 1: It has a right angle (90°), and the other two angles appear to be unequal. But without measuring, how do we know?

Hold on — perhaps the worksheet expects us to assume standard values or recognize common triangles.

Alternatively, maybe all three triangles are drawn so that their angles add to 180° — which they always do!

Let me re-read the instruction:

> “When you have finished measuring your angles, add up the angles in each triangle and write the total in the middle of the triangle. What do you notice?”

Ah — the key point is: no matter what kind of triangle you draw, the three angles inside will always add up to 180 degrees.

That’s the big idea here.

So even if we don’t have exact measurements, we can say:

- In Triangle 1: Angles = ? + ? + 90° → but total must be 180°
- In Triangle 2: All angles look acute — probably around 60° each? That would make it equilateral → 60+60+60=180
- In Triangle 3: Looks scalene — one obtuse angle? Still, total must be 180

But since we can’t measure, and the question says “what do you notice?”, the answer is likely about the sum being constant.

However, let’s try to estimate reasonable values for each triangle based on typical drawings.

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Triangle 1: Right Triangle

Assume it's a 30-60-90 triangle? Or 45-45-90?

Looking at the sides: The vertical side and horizontal side seem different lengths — so probably NOT 45-45-90.

If it were 30-60-90, then angles would be 30°, 60°, 90° → sum = 180°

That fits.

Triangle 2: Looks like an equilateral triangle?

All sides appear roughly equal, all angles look same → so 60°, 60°, 60° → sum = 180°

Triangle 3: Scalene triangle — one angle looks obtuse (>90°)

Suppose angles are approximately: 120°, 30°, 30°? Sum = 180°
Or maybe 100°, 50°, 30°? Also 180°

Doesn’t matter — as long as they add to 180.

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So regardless of the type of triangle, when you add the three interior angles, you always get 180 degrees.

That’s what you’re supposed to notice.

Therefore, for each triangle, the total written in the middle should be 180.

And the thing you notice is:
👉 *The sum of the interior angles of any triangle is always 180 degrees.*

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Final Answer:
For each triangle, the sum of the angles is 180°. You notice that no matter the shape or size of the triangle, the three interior angles always add up to 180 degrees.