Answer:
A right triangle
Explanation:
If you plot the triangle as in the figure below, it looks like a right triangle.
It should satisfy Pythagoras' Theorem:
AB² + AC² = BC²
Each side of the triangle is the hypotenuse of a smaller right triangle.
(2² + 4²) + (2² + 1²) = (4² + 3²)
(4 + 16) + (4 + 1) = 16 + 9
20 + 5 = 25
25 = 25
The theorem is satisfied. ∆ABC is a right triangle.