Values of Significant Angles

## Values of Significant Angles

The trigonometric values of certain angles should be known:

Angle Sin Cos Tan
0 1 0
30º frac(1)(2) frac(√3)(2) frac(1)(√3)
45º frac(1)(√2) frac(1)(√2) 1
60º frac(√3)(2) frac(1)(2) sqrt(3)
90º 1 0 undefined

The entry for tan 90º is undefined as the value is infinity.

## Example 1

What is the value of the angle ABC?

The adjacent and opposite values are known.

The tan of an angle is given by frac(text(opp))(text(adj)) = frac(2)(2) = 1.

The angle with a tan value of 1 is 45º

The sine of the angle is given by frac(text(opp))(text(hype)) = frac(sqrt(3))(2) = 60º