Answer:
solution given:
for rectangle
length [l]=18km
breadth [b]=7√3 km
for triangle
base[b1]=25-18=7km
height [h]=b=7√3km
for area :area of. (rectangle +triangle}=
l×b+1/2 b1×h=18×7√3+1/2 ×7×7√3=260.67km²
now
perimeter=sum of all sides
=18+14+25+7√3=69.12km
is your answer