Answer:
No, it is not a right triangle.
Explanation:
The diagonal slide, the stairs and the horizontal path form a triangle.
If the triangle is a right triangle, then it will satisfy the Pythagorean equation,
a² + b² = c²
If this were a right triangle, then the legs would by the path and the stairs.
a² + b² = 7² + 9² = 49 + 81 = 131
c² = 11² = 121
131 ≠ 121
Answer: No, it is not a right triangle.