Step 1:

\

From the triangle angle $\"\"$ and two sides $\"\"$

\

Find the side $\"\"$ by using law of cosines.

\

Law of cosines: $\"\"$ .

\

Substitute $\"\"$ , $\"\"$ in above formula.

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Step 2:

\

Find the angle $\"\"$ by using law of sines.

\

Law of sines: $\"\"$ .

\

Consider $\"\"$

\

Substitute $\"\"$ , $\"\"$ in above formula.

\

$\"\"$

\

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

\

$\"\"$

\

\

$\"\"$ .

\

Angle $\"\"$ .

\

Step 3:

\

Sum of the three angles in a triangle $\"\"$ .

\

$\"\"$

\

Substitute $\"\"$ and $\"\"$ in above expression.

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Solution:

\

$\"\"$ , $\"\"$ and $\"\"$

\

\

\