Find side BA, given all angles an one side of right triangle

[jeffg130]

ok so you have a right triangle and it is ABC lets say B is 90 A is 36 and C is 54. side AC is 12 how do you find side BA.
A#
#---#
#--54---#
#---------- #
#-------------#
#----------------# 12 units
#------------------#
#---------------------#
#-----------------------#
#-------------------------#
#---------------------------#
#--90------------------36----#
B##################C

 

[skeeter]

use the trig ratios you learned in class ...

sin(36) = (opposite side)/(hypotenuse) = (AB)/12,

or you can use cos(54) = (adjacent side)/(hypotenuse) = (AB)/12

so ... AB = 12sin(36) or AB = 12cos(54)