Use Sine Rule
a/sinA = b/sinB = c/sinC
to find missing lengths & angles.
Use Area = 1/2abSinC to calculate the area
The sides are represented as: a, b, and c.
s stands for half the periimeter.
If you follow all the steps that have been given to you, you will have the lengths of the three sides.
After that, it's just plug and chug.