sin x = opposite side / hypotenuse (the hypotenuse is the longest side ) so sin A in the given triangle = 5 / 13
cos x = adjacent side / hypotenuse. The adjacent side to angle A is AC so cos A = AC / 13
tan x = opposite side / adjacent side In the diagram tan A = 5 / AC
csc x = 1 / sin x = H / O ( H=hypotenuse and O = opposite) side
sec x = 1 / cos x = H/ A ( A = adjacent side)
cot x = 1 / tanx = A / O
In the triangle AC^2 = 13^2 - 5^2 = 144 so AC = 12 ( By Pythagoras)