Assuming biological substances are 90% water and the density of water is 1000 kg/meter cubed, estimate the mass of a fly, which can be approximated by a cylinder 4 mm long and 2 mm in diameter (volume (length*pi*radius squared)

the answer is 1.131 X10 to the negative 5th power. I just need to know how to get that answer. I calculated the volume to be 12.56. please help

Remember that the biolgical substances are only 90% water, meaning that the density we need to use is (1.0x10+3)90% which will be 9.0x10+2