His square paintings take up 36 square feet each because 6 x 6 = <<6*6=36>>36
His small paintings take 6 square feet each because 2 x 3 = <<2*3=6>>6
His large painting takes up 150 square feet because 10 x 15 = <<10*15=150>>150.
Combined, his square paintings take up 108 square feet because 3 x 36 = <<3*36=108>>108
Combined, his small paintings take up 24 square feet because 4 x 6 = <<4*6=24>>24
In total, his paintings take up 282 square feet because 150 + 108 + 24 = <<150+108+24=282>>282
#### 282