The diameter of a bacterial colony is 15.5 mmCalculate the cross-sectional area in mm2:_____ mm2Use the maths keyboard to write your answer in standard form and to three significant figures.
Question
The diameter of a bacterial colony is 15.5 mmCalculate the cross-sectional area in mm2:_____ mm2Use the maths keyboard to write your answer in standard form and to three significant figures.
Solution 1
To calculate the cross-sectional area of a bacterial colony, we can use the formula for the area of a circle, which is πr². However, we are given the diameter, not the radius. The radius is half the diameter, so in this case, the radius is 15.5 mm / 2 = 7.75 mm.
Now we can substitute the radius into the formula:
Area = π * (7.75 mm)² = π * 60.0625 mm² = 188.495559215 mm²
Rounding to three significant figures, the cross-sectional area of the bacterial colony is 188 mm².
Solution 2
The cross-sectional area of a circle is calculated using the formula A = πr², where r is the radius of the circle.
Step 1: Convert the diameter to radius. The radius is half of the diameter, so r = 15.5 mm / 2 = 7.75 mm.
Step 2: Substitute the radius into the formula. A = π * (7.75 mm)² = π * 60.0625 mm² = 188.495559215 mm².
So, the cross-sectional area of the bacterial colony is approximately 188.5 mm² to three significant figures.
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