In the diagram are two concentric circles of ra... - JAMB Mathematics 2002 Question
A
\(\frac{5}{9} \pi R^2\)
B
\(\frac{21}{25} \pi R^2\)
C
\(\frac{21}{23} \pi R^2\)
D
\(\frac{9}{25} \pi R^2\)
correct option: b
A\(\text{shaded portion}\) = \(\pi R^2 - \pi r^2\) r = \(\frac{2}{5}\)R
A\(\text{shaded portion}\) = \(\pi R^2 - \pi (\frac{2}{3} R)^2 = \pi R^2 - \frac{4 \pi R^2}{25}\)
= \(\pi R^2(1 - \frac{2}{3}) = \frac{21}{25} \pi R^2\)
A\(\text{shaded portion}\) = \(\pi R^2 - \pi (\frac{2}{3} R)^2 = \pi R^2 - \frac{4 \pi R^2}{25}\)
= \(\pi R^2(1 - \frac{2}{3}) = \frac{21}{25} \pi R^2\)
Please share this, thanks:
Add your answer
No responses