Answer:
A, B and C.
Step-by-step explanation:
If its a right triangle then c^2 = a^2 + b^2 where a, b and c are the 3 sides, c being the hypotenuse.
3^2 + 6^2 = 9 + 36 = 45
and (√45)^2 = 45 so the first set (A) is a right triangle.
2.5^2 + 6^2 = 6.25 + 36 = 42.25.
6.5^2 = 42.25 so B is also a right triangle.
C:
4^2 + 8^2 = 16 + 64 = 80
(√80)^2 = 80 so C is right-angled also.
