to find X you need to add up the other two angles inside the triangle which are 36 and 63, that equals 99 and then subtract that number from 180, which equals 81.
To find Z you will follow the 180 rule and subtract 180 from what you got for X(81), this will equal 99
To find Y you will add what you got for Z(99) plus 13 and then subtract that number from 180, which will give you 68
