If we know the square of a + the square of B + the square of C - AB BC AC = 0, we can judge the size relation of ABC quickly

If we know the square of a + the square of B + the square of C - AB BC AC = 0, we can judge the size relation of ABC quickly

Square of 2A + square of 2B + square of 2C - 2ab-2bc-2ac = 0
Square of (a-b) + square of (A-C) + square of (B-C) = 0
a=b=c