fpb dari 85,90 dan 102

85 = 5 x 17
90 = 3^2 x 5 x 2
102 = 2 x 3 x 17

karena tdk ada yg sama , maka fpb nya = 1

.............85......90.........102
: 2.........85......45...........51
: 3..........85.......15...........17
: 3...........85........5...........17
: 5...........17..........1............17
: 17...........1.............1............1

FPB = 1