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15Q20M

Perimeter of rectangles · 3 problems

From the 15Q20M Grade 4 workbook (Days 57–63) · Pencil, no calculator

Name:

  1. 1.

    A rectangular garden has a length of 16 m and a perimeter of 50 m. What is the width of the garden?

    Answer:

  2. 2.

    A rectangular deck is 14 m long and 8 m wide. A path 1 m wide is built around the outside. What is the perimeter of the outer edge of the path?

    Answer:

  3. 3.

    A yard is 10 m long and 8 m wide. A 2-meter gate is built into one side. How many meters of fence panels (not including the gate) are needed?

    Answer:

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Answer key (for parents)

Answer key: Perimeter of rectangles

  1. 1.

    9

    P = 2 × (l + w). So 50 = 2 × (16 + w). Divide both sides by 2: 25 = 16 + w. w = 25 − 16 = 9 m.

  2. 2.

    52

    The path adds 1 m on each side. Outer length = 14 + 2 = 16 m. Outer width = 8 + 2 = 10 m. P = 2 × (16 + 10) = 2 × 26 = 52 m.

  3. 3.

    34

    P = 2 × (10 + 8) = 2 × 18 = 36 m. 36 − 2 = 34 m of fence panels.

Equivalent answers count as correct: 2/4 for 1/2, 0.5 for 1/2, and so on.