$\"\"$

\

The sides of the triangle are $\"\"$ , $\"\"$ and $\"\"$ .

\

Find the three angles by using the Cosine Law.

\

Cosine law: $\"\"$ .

\

$\"\"$

\

Substitute $\"\"$ , $\"\"$ and $\"\"$ in $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

\

$\"\"$

\

Cosine law: $\"\"$ .

\

$\"\"$ .

\

Substitute $\"\"$ , $\"\"$ and $\"\"$ in $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

\

$\"\"$

\

The sum of angles in a triangle is $\"\"$ .

\

Substitute $\"\"$ and $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

\

The angles are $\"\"$ , $\"\"$ and $\"\"$ .

\

$\"\"$

\

The angles are $\"\"$ , $\"\"$ and $\"\"$ .