Use the Math.Atan
,
Math.Acos
, or Math.Asin
static
methods of the Math
class. The following code
calculates the angle theta
and returns the value
in radian measure:
double theta = Math.Atan(OppositeSide / AdjacentSide); theta = Math.Acos(AdjacentSide / Hypotenuse); theta = Math.Asin(OppositeSide / Hypotenuse);
To get the angle in degrees, use the following code:
double theta = Math.Atan(oppositeSide / adjacentSide) * (180 / Math.PI); theta = Math.Acos(adjacentSide / hypotenuse) * (180 / Math.PI); theta = Math.Asin(oppositeSide / hypotenuse) * (180 / Math.PI);
where theta
is the known angle value, the
oppositeSide
is equal to the length of the side
opposite to the angle, and
adjacentSide
is equal to the length of the side
adjacent to the angle. The
hypotenuse
is the
length of the hypotenuse of the triangle. See
Figure 1-1 in Recipe 1.14
for a graphical representation of these sides of a right triangle.
In some cases, we need to determine an angle of a right triangle when
only the lengths of two sides are known. The three trigonometric
functions
arcsine, arccosine, and arctangent allow
us to find any angle of a right triangle, given this information. The
static methods Math.Atan
,
Math.Acos
, and Math.Asin
on the
Math
class provide the functionality to implement
these trigonometric operations.
See Recipe 1.14; see the “Math Class” topic in the MSDN documentation.