Let’s solve each problem one by one. Remember:
Perimeter of a rectangle = 2 × (Length + Width)
So, if we know the perimeter and one side, we can find the other side.
We’ll rearrange the formula to solve for the missing side:
→ If you know
width, then:
Length = (Perimeter ÷ 2) – Width
→ If you know
length, then:
Width = (Perimeter ÷ 2) – Length
Let’s go step by step.
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Problem 1: Perimeter = 38 yd, Width = 7 yd → Find Length
Half of perimeter = 38 ÷ 2 = 19
Length = 19 – 7 =
12 yd
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Problem 2: Perimeter = 44 in, Length = 12 in → Find Width
Half of perimeter = 44 ÷ 2 = 22
Width = 22 – 12 =
10 in
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Problem 3: Perimeter = 72 ft, Width = 10 ft → Find Length
Half of perimeter = 72 ÷ 2 = 36
Length = 36 – 10 =
26 ft
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Problem 4: Perimeter = 100 ft, Length = 30 ft → Find Width
Half of perimeter = 100 ÷ 2 = 50
Width = 50 – 30 =
20 ft
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Problem 5: Perimeter = 86 yd, Width = 15 yd → Find Length
Half of perimeter = 86 ÷ 2 = 43
Length = 43 – 15 =
28 yd
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Problem 6: Perimeter = 30 in, Length = 9 in → Find Width
Half of perimeter = 30 ÷ 2 = 15
Width = 15 – 9 =
6 in
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Problem 7: Perimeter = 58 in, Width = 8 in → Find Length
Half of perimeter = 58 ÷ 2 = 29
Length = 29 – 8 =
21 in
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Problem 8: Perimeter = 12 ft, Length = 4 ft → Find Width
Half of perimeter = 12 ÷ 2 = 6
Width = 6 – 4 =
2 ft
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Problem 9: Perimeter = 64 yd, Length = 14 yd → Find Width? Wait — it says “Find Length” but gives length as 14 yd? Let me check again.
Looking at the image description: Problem 9 shows a rectangle with “14 yd” on top (so that’s the width), and asks for “Length”. So actually, 14 yd is the
width, not the length.
So: Perimeter = 64 yd, Width = 14 yd → Find Length
Half of perimeter = 64 ÷ 2 = 32
Length = 32 – 14 =
18 yd
*(Note: In rectangles, sometimes labels are placed on sides — if 14 yd is written on the top/bottom, it’s usually the width; left/right is height/length. But since the question says “Find Length”, and 14 yd is given on the horizontal side, we treat 14 yd as width.)*
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Final Answer:
1) Length = 12 yd
2) Width = 10 in
3) Length = 26 ft
4) Width = 20 ft
5) Length = 28 yd
6) Width = 6 in
7) Length = 21 in
8) Width = 2 ft
9) Length = 18 yd
Parent Tip: Review the logic above to help your child master the concept of perimeter worksheet with missing sides.
