Help please, I'm stuck on this

Aright triangle has an area of 18 square inches. b: if the triangle is not an isosceles triangle, what are all the possible lengths of the legs, if the lengths are whole numbers. answer !

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.

Identify the converse of the following conditional: if a point is in the first quadrant, then its coordinates are positive. if the coordinates of a point are not positive, then the point is not in the first quadrant. if the coordinates of a point are positive, then the point is in the first quadrant. if a point is in the first quadrant, then its coordinates are positive. if a point is not in the first quadrant, then the coordinates of the point are not positive.