Among the three interior angles of a triangle, it is known that ∠1=45° and ∠2=55°, so what is ∠3=?
在三角形的三个内角中，已知∠1=45°，∠2=55°，那么∠3=多少．
<gadget id="calculator">180 - 45 - 55</gadget>
<output>80</output>

<result>80</result>