# Sine

In math, sine (sin) is a trigonometric function that relates an angle to a specific ratio in a right-angle triangle. The sine of an angle is defined as the ratio of the length of the side opposite the angle (opposite) to the length of the longest side of the triangle (hypotenuse).

• The sine of an acute angle is defined in the context of a right-angled triangle, but can be applied to any angle using the unit circle.
• In the context of angles and triangles, “acute” refers to an angle that is greater than 0 degrees and less than 90 degrees.
• For any given angle, its sine is the ratio of the length of the side opposite that angle to the length of the longest side of the triangle (the hypotenuse).
• The maths notation for sine is sin.
###### References
• In math, sine (sin) is a trigonometric function that relates an angle to a specific ratio in a right-angle triangle. The sine of an angle is defined as the ratio of the length of the side opposite the angle (opposite) to the length of the longest side of the triangle (hypotenuse).
• The sine of an acute angle is defined in the context of a right-angled triangle, but can be applied to any angle using the unit circle.
• In the context of angles and triangles, “acute” refers to an angle that is greater than 0 degrees and less than 90 degrees.
• For any given angle, its sine is the ratio of the length of the side opposite that angle to the length of the longest side of the triangle (the hypotenuse).
• The maths notation for sine is sin.