Question 830177
Q:
In triangle ABC, the measure of angle A equals {{{ x^2+12 }}}, the measure of angle B equals {{{ 11x+5 }}} and the measure of angle C equals {{{ 13x-17 }}}. Determine the longest side of triangle ABC. 
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A:
m∠A + m∠B + m∠C = 180°
{{{ (x^2+12) + (11x+5) + (13x-17) = 180 }}}
{{{ x^2+ 24x - 180 = 0 }}}
(x - 6)(x + 30) = 0
x = 6, disregard x = -30 because it will make some angles negative
m∠A = {{{ 6^2+12 }}} = 48°
m∠B = 11(6) + 5 = 71°
m∠C = 13(6) - 17 = 61°
The longest side is opposite the largest angle.
The largest angle is ∠B and the side opposite ∠B is AC.
Therefore, the longest side is AC.