pake cara tolong jawabanya ya

3.
diket.:
d= 28 cm
r= 14 cm
sudut= 108

L=sudut/360 *2*π*r*r= 108/360 *2*22/7 *14*14= 184,8 cm^2
jawaban: C

4.
diketahui:
BC=18 cm
AOC= 120

COB= 180-120= 60
BC=COB/360 *2*π*r
18= 60/360 *2*π*r
r= 18*360/(60*2*π)= 54/π cm

AC= AOC/360 *2*π*r= 120/360 *2*π*54/π = 1/3 *108= 108/3
AC= 36 cm
jawaban: D.