Hi, The conventional way to define the trig functions is to start with an acute

**angle**that is an**angle**with measure**theta**between 0 and 90 degrees. You then draw a right triangle having one**angle**with measure**theta**degrees and label the three sides.Similarly, you may ask, what does Theta symbolize?

In ancient times, Tau was used as a symbol for life or resurrection, whereas the eighth letter of the Greek alphabet,

**theta**, was considered the**symbol of**death.What is the letter for Theta?

**Theta**(uppercase/lowercase Θ θ), is the

**letter**that means "think" in phonetics and also, of the Greek alphabet, used to represent the "th" sound in Ancient and Modern Greek. In the system of Greek numerals, it has a value of 9. The Cyrillic

**letter**Ѳ came from

**Theta**.

What does the theta symbol mean in trigonometry?

To define the

**trigonometric**functions of an angle**theta**assign one of the angles in a right triangle that value. The functions sine, cosine, and tangent can all be defined by using properties of a right triangle. A right triangle has one angle that**is**90 degrees. The longest side of the triangle**is**the hypotenuse.