Final answer:
The sine of 30 degrees (sin 30°) is a well-known trigonometric value equal to 1/2 or 0.5, derived from the ratio of the opposite side to the hypotenuse in a right-angled triangle.
Step-by-step explanation:
The question 'What is sin 30°' falls under the subject of trigonometry, which is a branch of Mathematics. To answer this, we can use the known values for sine of standard angles.
The sin 30°, also known as sine of 30 degrees, is a commonly memorized value in the unit circle and it is equal to 1/2 or 0.5. This is because a 30-degree angle in a right triangle corresponds to the ratio of the opposite side (half the hypotenuse of an equilateral triangle split down the middle) to the hypotenuse, hence sin 30° = 1/2.