Nursing Entrance Exam

Nursing Preparation Study Guide

4.3.4 Circles A circle is not a polygon since it does not have any straight sides. However, it is a type of geometric figure you need to know for your TEAS exam. A circle is defined as a circular enclosed figure which has no edge or vertex. Circle can also be defined as the combination of all those points in a plane area which are positioned at a fixed distance from a fixed central point. This fixed distance is known as the radii while the fixed point is known as the center of the circle. Hence, any line joining the center of the circle with any point on the circle is known as radius. Any line joining any two points on the circle is called a chord. It should be noted that a chord may or may not pass through the center of the circle. The chord that passes from the center is the largest line and is termed as the diameter of the circle. Diameter is twice the radius. 4.3.5 Congruent Circles Two circles are said to be congruent if they have same radius. That is, if we move one of the circles over the other, then they both with coincide. The circle with center O and radius r is congruent to circle with center and radius , if and only if = . Circumference: the perimeter of a circle is known as circumference and is enclosed with a definite length which is calculated by using the formula: Circumference = 2 Where, is a constant and denotes the length of the radius of the circle. Area : The area of the circle can be calculated using the following formula: Area = 8 4.3.6 Types of Angles • Central Angle: an angle whose vertex is located on the center of a circle and whose sides are two radii of the circle interesting on the edge of a circle.

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