So it's going to be square root of 3. Let me do that in that same yellow color. It's going to be, make sure I switch colors, it's going to be square root of 3 over 4 times the side squared, times x over 3 squared. All I did is the length of a side is x over 3. We already know what the area is. It's square root of 3 over 4 times the length of a side squared. And then the area of this square right over here, the area of the square is just going to be 100 minus x over 4 squared.