Answer:
The sine of an angle in a right triangle is the ratio of the length of the side adjacent to that angle to the length of the hypotenuse.
FALSE.
Explanation:
Given:
Diagram is attached below as
Consider, Δ ABC a Right Angle Triangle at ∠ C = 90°
AB = Hypotenuse
Solution:
In Right Angle Triangle Δ ABC , apply sine identity to angle B we get

i.e
The sine of an angle in a right triangle is the ratio of the length of the side OPPOSITE to that angle to the length of the hypotenuse... TRUE
Also For Cosine we have

The Cosine of an angle in a right triangle is the ratio of the length of the side adjacent to that angle to the length of the hypotenuse. ... True
The sine of an angle in a right triangle is the ratio of the length of the side adjacent to that angle to the length of the hypotenuse. ...FALSE