# How do i find the missing angles of a triangle?

Feb 21, 2018

By using any of these methods :-

#### Explanation:

1) use the fact that sum of all the angles of a triangle ia $180$ degree.

2) use Sine formula. $\left[\frac{a}{\sin} A = \frac{b}{\sin} B = \frac{c}{\sin} C\right]$

3) use Cosine formula.$\left[\cos A = \frac{{b}^{2} + {c}^{2} - {a}^{2}}{2 b c}\right]$

$\rightarrow$where $A$ denotes $\angle A$

$\rightarrow$ $a$ denotes side opposite to $\angle A$