In trapezoid NDKF, NL and DG are altitudes, m∠F=45º, m∠K=30º, DG=8, and ND=10. Find DK, GK, FN, m∠GDK, m∠FNL, and the perimeter
GK - solve using elementary trig (SOHCAHTOA) DK - Solve using pythagoras with your newly found GK FN - solve using pythagoras Angle GDK can be solved by the assumption that all angles inside a triangle add up to 180 degrees. You can subtract 90 (right angle) and the 30 degrees to get your answer. Angle FNL can be found similarly. The perimeter should be easy to calculate now.
|dw:1336051474241:dw| GD/DK = sin30 8/DK = 1/2 (or) DK = 16 GD/GK = tan30 8/GK = 1/srqt3 GK = 8sqrt3 LN/FN = sin45 8/FN = 1/sqrt2 FN = 8sqrt2 In triangle GDK, 90 + 30 + angleGDK = 180 Angle GDK = 60 In traingle FNL, 90 + 45 + angleFNL = 180 angleFNL = 45 Perimeter = ND + DK + GK + GL + FL + FN = 10 + 16 + 8sqrt3 + 10 + 8 + 8sqrt2 = 34 + sqrt3 + sqrt2
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