Question 1144388
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<pre>
Let x be the angle measure in degrees (now unknown).


Then the supplement angle measure is (180-x) degrees.


The condition says


    180°-x = 3x - 10°.


It is your basic equation.


Simplify and solve it for x, step by step.


    180 + 10 = 3x + x

    190      = 4x

      x      = {{{190/4}}} = 47.5.


<U>ANSWER</U>.  The angle is 47.5°.


<U>CHECK</U>.   The supplement angle is  180° - 47.5° = 132.5°.

          Thrice the angle is  3x = 3*47.5 = 142.5.

          132.5° = 142.5° - 10°.    ! Correct !
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Solved.