Page 16 - Mathematics Teaching Material Two Dimensional Figure
P. 16
Mathematics Teaching Material Two Dimensional Figure
4. Circle
What is a circle ?
circle is a the set of all points in a plane planes are equidistant from
a fixed point on
that field.
The radius and diameter of a circle Notice the circle with center
0 on the side.
The distance from the center to any point on the circle is called
circle radius. In the figure the distance O to point A is equal to
the distance point O to point B which in this case is the radius of
the circle.
The radius of a circle is usually denoted by The diameter of a
circle is the length of the straight line segment that through the
center point and connects two points at point O.
From the picture above we can conclude the properties of a parallelogram:
1. It has no vertices and the sum of the angles is 360 degrees
2. Has a radius (r) and a diameter (d)
3. Diameter = 2.r
4. Perimeter = 2πr or d
5. Has infinite folding symmetry
6. Has infinite rotational symmetry
Area of a circle = ×
Around = 2 x
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