Perimeter online exercise for Grade 2-3 - Free Printable

Let's solve each problem step by step to find the perimeter of each shape. Remember:

> Perimeter = sum of all side lengths

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1. Rectangle (Blue)

- Sides: 8 cm, 5 cm, 8 cm, 5 cm
- Perimeter = 8 + 5 + 8 + 5 = 26 cm

✔ Answer: 26 cm

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2. Triangle (Green)

- Sides: 6 in, 4 in, and one missing side marked with "?"
- But wait — it looks like a triangle with two sides labeled: 6 in and 4 in, and the third side is unknown.
- However, since it’s not specified as an equilateral or isosceles triangle, and no angle is given, we cannot assume anything about the missing side.

But looking at the image again:
- The triangle appears to be scalene, but only two sides are labeled: 6 in and 4 in.
- The third side is marked with a "?" — which might mean we're supposed to assume it's not given, but that can't be right because we need all sides to calculate perimeter.

Wait — actually, upon closer inspection, all three sides are shown, but only two are labeled:
- One side is 6 in (top),
- One side is 4 in (base),
- And the third side (left side) is marked with a "?", meaning it's unknown.

This is a problem — we cannot compute the perimeter unless all sides are known.

But this seems like a mistake — perhaps the triangle is meant to be equilateral? No, because sides are different.

Alternatively, maybe the triangle is isosceles, so the two equal sides are both 6 in?

But the base is 4 in, and one side is 6 in, and the other is unknown.

Unless... wait — is the triangle right-angled? We don’t have enough info.

But here’s the key: if it's a regular triangle, it would be equilateral — but the sides are different.

Wait — perhaps the triangle has sides:
- 6 in, 6 in, and 4 in? That would make sense if it's isosceles.

But only one side is labeled 6 in, and the base is 4 in.

Looking at the image carefully:
- Top side: 6 in
- Base: 4 in
- Left side: ? (no label)
- Right side: no label

So we have only two sides labeled, and the third is missing.

But that can't be — we need all sides.

Wait — perhaps the triangle is equilateral? But then all sides should be equal, but one is 6 in and one is 4 in → contradiction.

Hmm.

Wait — maybe the triangle is labeled incorrectly?

Let’s look again: the green triangle has:
- One side labeled "6 in" (top),
- One side labeled "4 in" (bottom),
- And the left side has a question mark.

No other labels.

So we cannot determine the perimeter unless more information is given.

But this is likely a mistake in labeling.

Wait — perhaps the triangle is isosceles, and the two equal sides are 6 in and 6 in, and base is 4 in?

That would make sense.

Or perhaps the triangle has sides: 6 in, 6 in, and 4 in?

But only one 6 in is labeled.

Alternatively, maybe the triangle is equilateral — but then all sides should be same.

But 6 ≠ 4 → impossible.

So unless there's a typo, we cannot solve this.

But let’s assume that the triangle is isosceles with two sides of 6 in and base 4 in — that’s common.

So sides: 6 in, 6 in, 4 in → perimeter = 6 + 6 + 4 = 16 in

But the image shows only one side labeled 6 in, and one 4 in.

Alternatively, could the missing side be 6 in too?

Possibility: the triangle has sides: 6 in, 6 in, and 4 in.

Then perimeter = 6 + 6 + 4 = 16 in

✔ Assuming it's isosceles with two sides of 6 in, answer is 16 in

But this is an assumption.

Wait — another possibility: maybe the triangle is right-angled?

Let’s suppose it's a right triangle with legs 6 in and 4 in, then use Pythagorean theorem.

But we don’t know which sides are legs.

If it’s a right triangle with legs 6 in and 4 in, then hypotenuse = √(6² + 4²) = √(36 + 16) = √52 ≈ 7.21 in → not nice number.

And the third side is marked with "?" — maybe it's asking us to find it?

But the task says: “Find the perimeter” — so we need all sides.

But we don’t have enough data.

Wait — perhaps the triangle has three sides: 6 in, 4 in, and the third side is also 6 in? So it's isosceles?

But only one side is labeled 6 in.

This is ambiguous.

But looking at the style of the worksheet, it's likely that the triangle is isosceles, and the two equal sides are both 6 in, and base is 4 in.

So:

- Sides: 6 in, 6 in, 4 in
- Perimeter = 6 + 6 + 4 = 16 in

✔ Answer: 16 in (assuming isosceles)

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3. Square (Pink)

- All sides: 4 ft
- Perimeter = 4 × 4 = 16 ft

✔ Answer: 16 ft

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4. Pentagon (Yellow)

- All sides: 7 mm
- It’s a regular pentagon (all sides equal)
- Perimeter = 5 × 7 = 35 mm

✔ Answer: 35 mm

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5. Octagon (Orange)

- 8 sides, each 2 cm
- Perimeter = 8 × 2 = 16 cm

✔ Answer: 16 cm

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6. Rectangle (Purple)

- Sides: 10 in and 3 in
- Opposite sides equal
- So sides: 10 in, 3 in, 10 in, 3 in
- Perimeter = 10 + 3 + 10 + 3 = 26 in

✔ Answer: 26 in

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Final Answers:

1. 26 cm
2. 16 in *(assuming isosceles triangle with two 6-inch sides)*
3. 16 ft
4. 35 mm
5. 16 cm
6. 26 in

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✔ Summary Table:

| Problem | Shape | Perimeter |
|--------|--------------|-----------|
| 1 | Rectangle | 26 cm |
| 2 | Triangle | 16 in |
| 3 | Square | 16 ft |
| 4 | Pentagon | 35 mm |
| 5 | Octagon | 16 cm |
| 6 | Rectangle | 26 in |

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⚠️ Note: For Problem 2, the triangle has insufficient labeling. If only two sides are given (6 in and 4 in), we cannot compute the perimeter without knowing the third side. However, based on typical worksheet design, it's likely intended to be an isosceles triangle with two sides of 6 inches and a base of 4 inches, giving a perimeter of 16 inches.

If you have additional information (e.g., it's a right triangle), the answer may differ.

Let me know if you'd like to explore that!