Problem
In triangle \( \mathrm{ABC} \) if \( (A B)^{2}<(B C)^{2}+(A C)^{2} \) then \( \angle C \) is
Solution
Step 1 ：\( (A B)^{2}<(B C)^{2}+(A C)^{2} \)
Step 2 ：\( \cos{\angle C} > 0 \)
Step 3 ：\(0 < \angle C < 90° \)
Step 1 ：\( (A B)^{2}<(B C)^{2}+(A C)^{2} \)
Step 2 ：\( \cos{\angle C} > 0 \)
Step 3 ：\(0 < \angle C < 90° \)
