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.
Question
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.
Solution
To calculate the cross-sectional area of a circle, we use the formula: Area = πr².
In this case, the diameter of the clear area is given as 8mm. The radius (r) is half of the diameter, so r = 8/2 = 4mm.
Substituting the radius into the formula gives: Area = π(4mm)² = 16π mm².
To one decimal place, this is approximately 50.3 mm².
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