The sketch of the diagram is given above
Given: j = 21 cm
and
[tex]\begin{gathered} Since we have a triangle, the total angle in a triangle is 180 degrees[tex]\begin{gathered}Having found all the angles, we will then use trigonometric identities to get the lengths of the other sides
We can use the sine rule
[tex]\begin{gathered} \frac{\sin39^0}{21}\text{ = }\frac{\sin 118^0}{l} \\ \\ To\text{ get l, we will cross multiply} \\ l\text{ = }\frac{\sin 118^0\text{ x 21}}{\sin 39^0} \\ \end{gathered}[/tex][tex]\begin{gathered} l\text{ = }\frac{18.5419}{0.6293} \\ \\ l\text{ = 29.46 cm} \end{gathered}[/tex]To get the area, we can use the relation
[tex]\text{Area = }\frac{1}{2}\text{ x l x j x sin 23 }[/tex]we have established that l = 29.46cm, j = 21cm
[tex]\text{Area = }\frac{1}{2}\text{ x 21 x 29.46 x 0.3907}[/tex]Area = 120.86 square centimeter
=> 120.9 square centimeters to the nearest tenth
