Step 1:

\

(1)

\

The angles of the triangle are $\"\"$ and $\"\"$ .

\

The side of the triangle is $\"\"$ .

\

Property of triangle : Sum of all angles in a triangle is $\"\"$ .

\

$\"\"$

\

Find $\"\"$ .

\

Sine law : $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Step 2:

\

(2)

\

The angles of the triangle are $\"\"$ and $\"\"$ .

\

The side of the triangle is $\"\"$ .

\

Property of triangle : Sum of all angles in a triangle is $\"\"$ .

\

$\"\"$

\

Find $\"\"$ .

\

Sine law : $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Step 3:

\

(3)

\

The angle of the triangle is $\"\"$ .

\

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

\

Find $\"\"$ .

\

Cosine law : $\"\"$ .

\

$\"\"$

\

Step 4:

\

(4)

\

The angle of the triangle is $\"\"$ .

\

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

\

Find $\"\"$ .

\

Cosine law : $\"\"$ .

\

$\"\"$

\

Solutions

\

(a) $\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$