Answer: The correct option is
(C) The triangle is not acute because 2² + 4² < 5².
Step-by-step explanation: We are to select the statement that best explains the type of the triangle having lengths of three sides as 2 inch, 5 inch and 4 inch.
We know that a triangle with side lengths a, b and c (c > a, b)is
(i) an acute-angled if a² + b² > c², and
(ii) an obtuse-angled if a² + b² < c².
For the given triangle,
a = 2 inch, b = 4 inch and c = 5 inch.
So, we have
so the given triangle is not acute, but obtuse.
Thus, the triangle is not acute because 2² + 4² < 5².
Option (C) is correct.