Question 847196
Good idea, but if that was the case then we'd have that the other leg would be sqrt(3)*x and not 2x. Notice that given two legs, we have the height and the base [it does not matter which is which].  So our area = 1/2 * b *h =  1/2 * x * 2x =  x^2. 

Domain: Now remember what x represents. It represents a distance. So our domain is all positive values of x. Or x>0.