Answer:
It is an acute triangle.
Step-by-step explanation:
It would be much easier for you to see where I'm getting at if you draw a diagram.
Assume this triangle is labelled ABC where a = 14, b = 21, and c = 16.
cos A = (16^2 + 21^2 - 14^2)/(2(16)(21))
∠A = cos^-1(0.82291...)
∠A ≅ 34.6°
cos B = 16^2 + 14^2 - 21^2)/(2(16)(14))
∠B = cos^-1(0.024...)
∠B ≅ 56.8°
∠C = 180 - (∠A + ∠B)
∠C ≅ 56.8°
Since there is no right-angle nor is there an obtuse angle,
Therefore the triangle is an acute triangle.
