Пусть EF=12. Треугольник KFL прямоугольный, угол L = 90°. KL=8.
KF = √(KL²+FL²) = √(8²+12²) = √(64+144) = √208 = 4√13
sin K = FL/KF = 12/(4√13) = 3/√13 = (3√13)/13
cos K = KL/KF = 8/(4√13) = 2/√13 = (2√13)/13
tg K = FL/KL = 12/8 = 3/2
ctg K = KL/FL = 8/12 = 2/3
Ответ: sin∠K = (3√13)/13, cos∠K = (2√13)/13, tg∠K = 3/2, ctg∠K = 2/3