A circle has circumference 22 cm.\nCompute its area in square centimetres.

Difficulty: Easy

77
38.5
44
88

Correct Answer: 38.5

Explanation:

Introduction / Context:
Again convert circumference to radius using C = 2 * pi * r, then area A = pi * r^2. This case is tailored to the exact fraction pi = 22/7.

Given Data / Assumptions:

C = 22 cm; take pi = 22/7.

Concept / Approach:
Isolate r, then square to compute area.

Step-by-Step Solution:

r = 22 / (2 * 22/7) = 22 * 7 / 44 = 3.5 cmA = pi * r^2 = (22/7) * (3.5)^2 = (22/7) * 12.25 = 22 * 1.75 = 38.5 cm^2

Verification / Alternative check:
C back = 2*pi*r = 2*(22/7)*3.5 = 22 cm.

Why Other Options Are Wrong:
They come from mis-squaring 3.5 or misplacing the 1/7 factor.

Final Answer:
38.5

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