Let’s solve each problem step by step. We’re finding the
perimeter — that means adding up all the sides of each shape.
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1) Rectangle: 6 in. and 2 in.
A rectangle has 4 sides: two long, two short.
→ Two sides are 6 inches → 6 + 6 = 12
→ Two sides are 2 inches → 2 + 2 = 4
→ Total perimeter = 12 + 4 =
16 inches
✔ Check: Formula is 2 × (length + width) = 2 × (6 + 2) = 2 × 8 = 16 ✔️
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2) Square: 10 in.
All 4 sides are equal.
→ 10 + 10 + 10 + 10 =
40 inches
✔ Or: 4 × 10 = 40 ✔️
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3) Triangle: 3 ft, 4 ft, 5 ft
Just add all three sides:
→ 3 + 4 + 5 =
12 feet
✔ Simple addition — no tricks here ✔️
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4) Octagon: Each side is 2 cm
An octagon has 8 sides.
→ 8 × 2 =
16 centimeters
✔ All sides same length → multiply number of sides by one side ✔️
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5) Cross: All sides are 5 in.
This looks like a plus sign made of squares. Let’s count how many outer edges there are.
Imagine it as 12 small segments around the outside (each 5 in).
You can trace the outline:
- Top arm: 3 sides exposed? Wait — better way: think of it as 12 unit-length edges if you break it down.
Actually, for this cross shape (made from 5 squares: center + 4 arms), the perimeter is
12 sides.
Each side is 5 inches → 12 × 5 =
60 inches
✔ Visual check: Each “arm” adds 3 new outer edges (top, left, right for top arm, etc.), but shared edges don’t count. Standard result for this cross: 12 outer edges. ✔️
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6) Parallelogram: 5 m and 2 m
Opposite sides are equal.
→ Two sides are 5 m → 5 + 5 = 10
→ Two sides are 2 m → 2 + 2 = 4
→ Total = 10 + 4 =
14 meters
✔ Same as rectangle formula: 2 × (side1 + side2) = 2 × (5 + 2) = 14 ✔️
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Final Answer:
1) 16 in.
2) 40 in.
3) 12 ft.
4) 16 cm.
5) 60 in.
6) 14 m.
Parent Tip: Review the logic above to help your child master the concept of free perimeter worksheet.
