Answer:
no
Step-by-step explanation:
Using the converse of Pythagoras' identity.
If the square of the longest side is equal to the sum of the squares on the other 2 sides then the triangle is right.
longest side = 18, and 18² = 324
11² + 16² = 121 + 256 = 377 ≠ 324
Then triangle is not right.