Graphics Reference
In-Depth Information
R
r
Fig. 10.15.
An annulus formed from two concentric circles.
r
a
Fig. 10.16.
A sector of a circle defined by the angle
α
.
Figure 10.16 shows a
sector
of a circle, whose area is given by
α
360
◦
πr
2
A
=
(10.21)
Figure 10.17 shows a
segment
of a circle, whose area is given by
A
=
r
2
2
(
α
−
sin(
α
))
(
α
is in radians)
(10.22)
The area of an
ellipse
with major and minor radii
a
and
b
is given by
A
=
πab
(10.23)
10.2 2D Analytical Geometry
In this section we briefly examine familiar descriptions of geometric elements
and ways of computing intersections.
10.2.1 Equation of a Straight Line
The well-known equation of a line is
y
=
mx
+
c
(10.24)
