Before this question can be answered you need to specify which intersection. Otherwise there is no way to answer this question.
It is the Gulf of Thailand, or Gulf of Siam.
Persian Gulf
The gulf of Oman
Gulf of Thailand
Thailand
The gulf of Oman
The Persian Gulf.
The Arabian Gulf
The gulf located east of the intersection of 100 E longitude and 10 N latitude is the Gulf of Thailand. This body of water lies in Southeast Asia, bordered by Thailand, Cambodia, and Vietnam. It is an important area for shipping and fisheries in the region.
There is no such coordinate as 100 degrees latitude, either north or south. The maximum latitude number is 90 degrees, at the north and south poles.
The Arabian Gulf
The Persian Gulf is located at 50 degrees east and 30 degrees north. It lays just to the southwest of Iran.