A. DEFINITION
OF CIRCLE
Circle
is a collection of dots, which formed one closed arch and the dots that are on
arch equidistant to center point.
1)
The
center point
is the midpoint of the circle, the distance of the
point to any point on the circle always remains. Point O is the center point of
the circle.
2)
Radius
of circle
is the
distance from the center point to the arc of a circle. The radius of the circle
indicated by the line OA, OB, OC.
3)
Bowstring
a line segment in a
circle which connect two points on a circle arch. AC line is bowstring circle.
4)
Arc
is a curve that is
located in the arc of the circle and connect any two points on the curve. AC
curve is a circular arc.
5)
Diameter
is the largest bowstring
that through the center point, and its length is twice the radius of the
circle. BC line is the diameter of the circle. This line divides the circle
into the same area.
6)
Apothem
is a line connecting
the center point of the circle with bowstring . It is perpendicular to the
bowstring. OD line is apothem.
7)
Circle
pie
is the area within a
circle bounded by two radius of a circle and an arc that flanked by both the
radius of the circle. AOB area is a circle pie.
8)
Borderline
is a circular area that
bounded by a bowstring and arc. The yellow area is borderline.
C. CHARACTERS OF CIRCLE
1) Having
a center point.
2) Only
consists of one side.
3) Not
having a vertex and the amount of the angle is 360 degrees
4) Having
radius (r) and diameter (d)
5) Having
an infinite fold symmetry
6) Having
an infinite rotational symmetry
Pi (π)
pi is a quantity which is the special nature of the circle, which is the ratio of the circumference (C) a circle to its diameter (d). Pi has been discovered by scientists earlier. Each of these scientists found that the value of pi approaching 3.14. The following equation pi (π) :
pi is a quantity which is the special nature of the circle, which is the ratio of the circumference (C) a circle to its diameter (d). Pi has been discovered by scientists earlier. Each of these scientists found that the value of pi approaching 3.14. The following equation pi (π) :
π
= (circumference) : (diameter of the circle)
Circumference of Circle
From the equation above, we can also know that the formula circumference of the circle equals pi times the diameter of the circle.
C = πd or C = 2πr
From the equation above, we can also know that the formula circumference of the circle equals pi times the diameter of the circle.
C = πd or C = 2πr
Area of Circle
Area of a circle can be calculated with dissect the circle as elements of a pie and then restructured into a rectangle, so that the area can be easily calculated. In pictures r means the same as the radius of the circle.
It
can be seen that from the circle as elements of a pie, they form a rectangle. So,
the area of a circle can be calculated using the formula for the area of a
rectangle. With a length = πr, width = r
Area
of a circle = Area of the rectangle
= Length x width
=
πr x r
=
πr2
Tidak ada komentar:
Posting Komentar