Subject: General Aptitude · Chapter: Area · Exam: · Marks: · Difficulty:
If $r$ and $R$ and the respective radii of the smaller and the bigger semi-circles then the area of the shaded portion in the given figure is : $\pi r^{2}$ sq. units
(b)$\pi R^{2}-\pi r^{2}$ sq. units
(c)$\pi R^{2}+\pi r^{2}$ sq. units
(d)$\pi R^{2}$ sq. units
Answer
Answer (as printed): D
Explanation
Area of the shaded portion = (Sum of areas of 2 smaller semi-circles + Sum of areas of 2 bigger semi-circles) - Sum of areas of 2 smaller semi-circles = Sum of areas of 2 bigger semi-circles $=\left(2 \times \frac{\pi R^{2}}{2}\right)$ sq. units $=\left(\pi R^{2}\right)$ sq. units.
Explanation as extracted from the printed page; notation may be imperfect.