Area of a Circle (Basics)

The ground one circle covers is found by an expression resting on the radius. Questions with the radius given straight out stand beside two-tier questions giving only the diameter, where the radius comes first, and the same expression is used both in calculation carrying a drawing with its measurements and in word problems opening from an everyday scene.

At the point of multiplying by 3.14 the decimal point slips and a figure a tenth or ten times the true one gets written in. The Area of a Circle comes out a little above three times the radius multiplied by itself, so setting that estimate beside the answer brings a slipped place straight into the open.

This is the first lesson of Area of a Circle, and what it handles is one unbroken circle alone. In Area of Semicircles and Sectors the ground found by the same expression gets cut according to the central angle.