Q.36 In the given figure, AOBCA represents a quadrant of a circle of radius 3.5 cm with centre O. Calculate the area of the shaded portion. Sol. Let radius of circle be r i.e. 3.5 cm Trigonometry: Unit Circle. example. Conic Sections: Circle.Thus, the area of sector S is related to the area A according to the ratio of α to 360°. We can once again derive a formula. Practice Problem: A central angle γ in a circle of radius 10 units forms a sector with an area of 2.62 square units. Find the measure of γ.

As for every regular polygon, the area of the regular pentagon equals perimeter times apothem time a half. Since it is a regular shape, we can modify the formula, so we only need the side of the shape or the radius of the circumscribed circle. Please choose one of them in the surface area calculator below, to obtain the results.