Have you learnt how to find centroids? If you have learnt it and you know how to calculate moments, go on and read the solution. If you don't know it yet, there's a nice video on how to find centroids here.
To find the centroid, we first have to find 3 things. 2 moments, and , and the area .
If the centroid's coordinates are ( ),
If a region is bounded by two curves and , and by two lines , , then,
Let's apply it to your question.
Our centroid is