Tolong! kerjain nomer 6 (beserta caranya)

LJOPQ=sudutPOQ/360° x luas O
19,25=45°/360° x luas O
19,25=1°/8° x luas O
luas O=19,25 x 8 = 154 cm^2

LJORS=sudutROS/360° x luas O
51,33=sudutROS/360° x 154
51,33=sudutROS/90° x 38,5
sudutROS/90°=51,33/38,5=1,3332
sudutROS=1,3332 x 90° = 119,9922° = 120°