The antibiotic called cefalexin created a clear area with a diameter of 18 mm.Calcualte the cross-sectional area in mm._____ mm2Use the maths keyboard to write your answer in standard form and to three significant figures.

The antibiotic called azithromycin created a clear area with a diameter of 21 mm.Calcualte the cross-sectional area in mm._____ mm2Use the maths keyboard to write your answer in standard form and to three significant figures.

A scientist has investigated the effectiveness of different antibiotics on the growth of E. coli.The diameter of the clear area around one of the antibiotic discs above is 8 mm.Calculate its cross-sectional area._____ mm2Write your answer to 1 decimal place.

Scientists investigated the effectiveness of different disinfectants on the growth of bacteria.The diameter of the clear area around one of the disinfectants is 9.2 mm.Calculate its cross-sectional area._____ mm2Write your answer to 1 decimal place.

A bacterial colony has a diameter of 16 mm.Calculate its cross-sectional area in mm2:_____ mm2Use the maths keyboard to write your answer in standard form and to three significant figures.I DON'T KNOWSUBMIT ANSWER

A scientist investigated the effect of different disinfectants on the growth of the bacterium, Bacillus subtilis.A disinfectant used to clean hospital floors left a zone of inhibition with a diameter of 24 mm.Calculate the cross-sectional area in mm._____ mm2Use the maths keyboard to write your answer in standard form and to three significant figures.