cosine (x) = 4 over 5
cos
(
x
)
=
4
5
Explanation:
First you must apply sohcahtoa
it means
sine = opposite side over hypotenuse
sine = opposite/hypotenuse
cosine = adjacent side over hypotenuse
cosine = adjacent/hypotenuse
tangent = opposite side over adjacent side
tangent = opposite/adjacent
then
solve the unknown by applying the Right Triangle Theorem.
draw a right triangle.
label the parts where
a
is the opposite side
b
is the adjacent side
c is the hypotenuse
Solve the unknown. The hypotenuse using
a
2
+
b
2
=
c
2
since the given
tan
x
=
3
4
it means
tan = opposite/adjacent
a
= opposite side =
3
b
= adjacent side =
4
c
= hypotenuse = ??
a
2
+
b
2
=
c
2
substitute the value
(
3
)
2
+
(
4
)
2
=
c
2
9
+
16
=
c
2
25
=
c
2
get the square root of
25
it is equal to
5
therefore
c
=
5
c
= hypotenuse =
5
cos
= adjacent/hypotenuse
cos
(
x
)
=
4
over
5
cos
(
x
)
=
4
5
