Discussion
The circumference and the area of a circle at radius 21 cm are
Answer: A
They are 132 cm and 1386 \(\text{cm}^{2}\), in that order.
\[ \begin{aligned} C &= 2\pi r = 2 \times \frac{22}{7} \times 21 = 132\ \text{cm} \\ A &= \pi r^2 = \frac{22}{7} \times 441 = 1386\ \text{cm}^2 \end{aligned} \]
The option 1386 cm2, 132 cm reverses the order the question asks for. The other two give a length and an area the same value or the wrong units: a circumference is a length in cm, and an area is in square centimetres.
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