What is cos B for the triangle shown

How do i get the answer for 2/3 * 10/3

Asilkworm winds its cocoon out of one long silk fiber. to make silk thread, 3 to 10 of these silk fibers are unwound from their cocoons and combined into aa single thread with a typical length of 300 yards. choose a reasonable number of silk fibers in a thread write an equation to find the total length of the silk fibersused in 300 yards of the thread

Which statement accurately explains whether a reflection over the x-axis and a 180° rotation would map figure acb onto itself?