Make a chart like the one below. It helps you quickly 'see' what needs to be figured out as well as helping you quickly find a strategy.
Determine the measure of angle G first. Then use the Law of Sines to calculate the missing side lengths.
Draw a height from vertex G ⊥ to side OD.
Using your calculation for side o and the sine function for angle D, find the height. Then use the area formula for a triangle.