Values of Significant Angles

# Values of Significant Angles

GCSE(F), GCSE(H),

The trigonometric values of certain angles should be known:

AngleSinCosTan
010
30ºfrac(1)(2)frac(√3)(2)frac(1)(√3)
45ºfrac(1)(√2)frac(1)(√2)1
60ºfrac(√3)(2)frac(1)(2)sqrt(3)
90º10undefined

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

## Examples

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