S1={z∈C:∣z∣≤5}

S2=Im(1−3iz+1−3i)≥0
Take z=x+iy
=1−3ix+iy+1−3i×1+3i1+3i
=S3=amp;1+3x+iy+1−3i+3ix−3y+3i+3amp;=y+3x≥0amp;x≥0

amp;y+3x=0amp;y=−3xamp; Slope =−3amp;90+θ=120∘amp;θ=30∘amp;90−θ=60∘
In first quadrant we have angle 2π
so, total angle 90∘+60∘=150∘
So, area 2ππr2×65π=12125π