Problem 1:
Set one: 5, 12, 13
Set two: 4, 9, 12
Notice that the first triangle satisfies Pythagorean theorem:
5^2 + 12^2 = 13^2
25 + 144 = 169
169 = 169, so it is a right triangle.
The second triangle does not follow Pythagorean theorem so it is not a right triangle.
Problem 2:
angle 1: 30°
angle 2: 60°
length of the side between the two angles: 25
Notice that the other sides are determined.
When you draw a segment with length 25, and then add two lines, one from each end of the given segment, one of the lines with angle 30° and the other one with angle 60°, the two lines will intersect each other forming a triangle.
The tirangle given is unique and you can check wheter it is rigth or not.