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Trigonometry

Source: 2018 AMC 12A #23

February 8, 2018
AMCAMC 12AMC 12 Atrigonometry2018 AMC 12A2018 AMC

Problem Statement

In PAT,\triangle PAT, P=36,\angle P=36^{\circ}, A=56,\angle A=56^{\circ}, and PA=10.PA=10. Points UU and GG lie on sides TP\overline{TP} and TA,\overline{TA}, respectively, so that PU=AG=1.PU=AG=1. Let MM and NN be the midpoints of segments PA\overline{PA} and UG,\overline{UG}, respectively. What is the degree measure of the acute angle formed by lines MNMN and PA?PA?
<spanclass=latexbold>(A)</span>76<spanclass=latexbold>(B)</span>77<spanclass=latexbold>(C)</span>78<spanclass=latexbold>(D)</span>79<spanclass=latexbold>(E)</span>80<span class='latex-bold'>(A) </span> 76 \qquad <span class='latex-bold'>(B) </span> 77 \qquad <span class='latex-bold'>(C) </span> 78 \qquad <span class='latex-bold'>(D) </span> 79 \qquad <span class='latex-bold'>(E) </span> 80