Plz help me solve these sums i will be great full

1.How many non congruent right triangles with positive integer leg lengths have areas that are numerically equal to 3 times their perimeters

2.A triangle with side lengths in the ratio 3:4:5 is inscribed in a circle of radius 3.What is the area the triangle

3.Two points A and B .Find the set of feet of perpendiculars dropped from the point A onto all possible straight lines passing through the point B.