Find the measure of ∠3 in the triangle below. ∠1=54°, ∠2=63°, ∠3=how many degrees.
算出下面三角形中∠3的度数．∠1=54°，∠2=63°，∠3=多少°．
<gadget id="calculator">180 - 54 - 63</gadget>
<output>63</output>

<result>63</result>