Answer:
write in calculator
2.9^2 +8.1^2
then the for the answer you get, square root it.
x=10 and y=6
(since it says congruent)
Pythagorean theorem: a² + b² = c²
to find out if these numbers make a triangle, you must put them into the pythagorean theorem
7² + 8² = 15²
49 + 64 =/= 225
so no, these numbers do not make a triangle. hope this helped! ♥