hitung keliling dan luas daerah arsir

a)kell=(3/4)(2)phi(r)
=(3/4)(2)(22/7)(10)
=47,14
luas=(3/4)(phi)(r²)
=(3/4)(22/7)(100)
=235,71
b)kell=(1/4)(2)phi(r)
=(1/4)(2)(3,14)(10,5)
=16,485
luas=(1/4)(phi)(r²)
=(1/4)(3,14)(110,25)
=86,54625

maaf jikajika salah semoga membantu