The terminal side of a first angle
in standard position contains the point
.
Consider radius at the point
as
.
Find
.
Pythagorean Theorem :
.

Trigonometric function :
.


The terminal side of a second angle
in standard position contains the point
.
Consider radius at the point
as
.
Find
.
Pythagorean Theorem :
.

Trigonometric function :
.
.
Relationship between sines of
and
is
.
Relationship between sines of
and
is
.