1st Year Maths Chapter 9 Solution.pdf

The word trigonometry has been derived from Greek words: trei (three), Gano (angles) and Metron (measurement). So it means measurement of triangle. Units of measure of Angles: Angle: two rays with a common starting point from an angle. One of the rays of angle is called initial side and the other as terminal side. An angle is said to be positive if the rotation is anti- clockwise. An angle is said to be negative if the rotation is clockwise. Angle are usually denoted by Greek letters ????(alpha) ????(????????????????) , ????(????????????????????), ????(????ℎ????????????)