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Circles, Circumference, and Area. Section 10-1. Circle:. Definition: A circle is the locus of points in a plane that are a fixed distance from a point called the center of the circle . A has radius r = AB and diameter d = CD. chords VT a nd WR secant: VT tangent: s diam.: WR
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Circles, Circumference, and Area Section 10-1
Circle: • Definition: A circleis the locus of points in a plane that are a fixed distance from a point called the center of the circle. • Ahas radius r= ABand diameter d= CD.
chords VT and WR secant: VT tangent: s diam.: WR radii: QW and QR Lesson Quiz: Part I 1. Identify each line or segment that intersects Q.
Measure the circumference and diameter of a circle and divide the circumference by diameter
Cirmumference C = πd
Example: A drum kit contains three drums with diameters of 10 in., 12 in., and 14 in. Find the circumference of each drum. 10 in. diameter 12 in. diameter 14 in. diameter C = d C = d C = d C = (10) C = (12) C = (14) C = 31.4 in. C = 37.7 in. C = 44.0 in.
You can use the circumference of a circle to find its area. Divide the circle and rearrange the pieces to make a shape that resembles a parallelogram. The base of the parallelogram is about half the circumference, or r, and the height is close to the radius r. So A r · r = r2. The more pieces you divide the circle into, the more accurate the estimate will be.
A = πr2 Find the area of the circle if its diameter is 10. Find the area of the circle if its circumference is 8π. Area of a Circle: