වර්ගඵලය — සා/පෙළ ගණිතය

Look at a circular kokis mould, a hand-held fan opened part-way, a slice cut from a birthday cake, or a pie-shaped plot of land marked out by a surveyor. Each is a piece of a circle — not the whole thing. In this lesson you learn to measure exactly how much surface such a piece covers. Once you can find the area of a sector, you can estimate cloth for a circular skirt, paint for a curved wall panel, or land in a wedge-shaped block — and you can handle the "unusual" shapes that O/L examiners love, where a rectangle carries a semicircle on top.