Question

A rectangular paper of 20 cm \( \times \) 8 cm is folded 3 times. Each fold is made along the line of symmetry, which is perpendicular to its long edge. The perimeter of the final folded sheet (in cm) is:

• A. \( 18 \)
• B. \( 24 \)
• C. \( 20 \)
• D. \( 21 \)

Hint:

When calculating the perimeter after folding, remember that folding changes only one dimension at a time.

Answer 1

The Correct Option is A

Step 1: Dimensions after each fold. Initially, the dimensions of the paper are \( 20 \, \text{cm} \times 8 \, \text{cm} \).
First fold: The paper is folded along the 20 cm side, resulting in dimensions \( 10 \, \text{cm} \times 8 \, \text{cm} \).
Second fold: The paper is folded along the new 10 cm side, resulting in dimensions \( 5 \, \text{cm} \times 8 \, \text{cm} \).
Third fold: The paper is folded along the new 8 cm side, resulting in dimensions \( 5 \, \text{cm} \times 4 \, \text{cm} \). Step 2: Calculate the perimeter. The perimeter of the final folded sheet is: \[ P = 2 \times (\text{length} + \text{breadth}) = 2 \times (5 + 4) = 18 \, \text{cm}. \] Final Answer: \[ \boxed{18 \, \text{cm}} \]