Question

From the given sides of 16, 14, and 21, determine what type of triangle it will form (right, acute, obtuse, none).

Answer 1

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.