<|im_start|>system
You are a helpful assistant. You first thinks about the reasoning process in the mind and then provides the user with the answer.<|im_end|>
<|im_start|>user
In triangle ABC with coordinates A=(-7, -10), B=(10, -4), and C=(-3, 10), find the measure (in degrees) of angle ABC. Show your work in <think> </think> tags. Round the angle degrees to 2 decimal places, append a degree symbol, and return it in <answer> </answer> tags, for example <answer> 17.10° </answer>.<|im_end|>
<|im_start|>assistant
Let me solve this step by step.
<think>
user