The document defines key terms related to circles such as radius, diameter, and circumference. It explains that the circumference of a circle can be calculated using the formula c=2πr or c=πd, and the area can be found with the formula a=πr^2. It then provides three examples of using these formulas to find the circumference of a circle with radius 6cm, the area of a circle with radius 13m, and the radius of a circle with area 255cm^2.

1. Geometry

2. circle: the set of all points in a place that are the same distance from a given point, called the center of the circle. radios : the distance from the center to a point on the circle. diameter : the distance a cross the circle, through the center. circumference : the distance around a circle. Circumference and Area of Circles

3. circumference : c=  d or c=2  r area : a=  r2 www.historyforkids.com

4. 1.Find the circumference of the circle. r = 6cm c = 2  r = 2(  ) (6) = 12  = 37.7cm = 38cm scienceray.com

5. 2. Find the area of the circle. 13m r = 13m a =  r2 =  (13)2 = 169  = 531m2 clas.ucsb.edu