In the triangle ABC, ∠A=80°, the degree of ∠B is 3 times of ∠C, ∠B=how many degrees.
在三角形ABC中，∠A=80°，∠B的度数是∠C的3倍，∠B=多少°．
<gadget id="calculator">180 - 80</gadget>
<output>100</output>

<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">100 / 4</gadget>
<output>25</output>

<gadget id="calculator">25 * 3</gadget>
<output>75</output>

<result>75</result>