To solve this question, we must use the cosine rule:
cos(A) = (b^2 + c^2 - a^2)/2bc, where A is the angle you want to find, a is the side opposite that angle, and b and c are the other two sides of the triangle.
Given that we know that a = 6, b = 12, c = 14, we can substitute these values into the formula to get:
cos(A) = (12^2 + 14^2 - 6^2)/2(12)(14)
cos(A) = (144 + 196 - 36)/336
cos(A) = 304/336
cos(A) = 19/21
A = cos-1(19/21)
A = 25° (to the nearest degree)