Find the area of the shape

You would have to find the area of the whole rectangle without the spece, so it would be 30mm x 15mm, the result would be 450 square mm.

Then you find the area of the empty space which would be 10mm x 8mm, the result: 80 square mm.

You substract the area of the space from the whole rectangle, which would be 370 square mm, this is the area of the figure