Standard Mathematics Primary 4 Area and Perimeter

Mr Tan is fencing a rectangular vegetable plot at his HDB community garden in Toa Payoh. He uses 64 cm of ribbon to mark the perimeter of a small scale model of the plot. The width of the rectangle is 12 cm. What is the length of the rectangle?

A 5 cm
B 20 cm
C 40 cm
D 52 cm
Show Worked Solution

Worked Solution

Step 1: Recall the perimeter formula for a rectangle: Perimeter = 2 × (length + width). Step 2: Substitute the known values: 64 = 2 × (length + 12). Step 3: Divide both sides by 2: 64 ÷ 2 = length + 12, which gives 32 = length + 12. Step 4: Subtract 12 from both sides: length = 32 − 12 = 20. Step 5: Check: 2 × (20 + 12) = 2 × 32 = 64 cm. ✓ Final answer: The length is 20 cm. Answer: 20 cm

Correct answer: 20 cm

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