1. Find a right triangle having area 5 and rational sides.
2. Same task for area=7.
I got this answer (and the part 1 answer) by examining Pythagorean triples.
The (175,288,337) right triangle has an area of 25200 = 7 * 3600,
so (175/60, 288/60, 337/60) has an area of 7.
Reducing gives (35/12, 24/5, 337/60) as an answer