# PreCal HW Help?

A colony of 2^120 bacteria occupies a total volume of 1.3 times 10^5 meters cubed. The surface area of a planet is approximately 6.84 times 10^14 meters squared.

a. Assume that the bacteria are distributed uniformly over the planet's surface. How deep would the bacterial layer be? (You can find the approximate depth by dividing the bacteria volume by the planet's surface area.)

(Round to the nearest thousandth as needed.)

### 5 Answers

- Anonymous9 months agoFavorite Answer
< (You can find the approximate depth by dividing the bacteria volume by the planet's surface area.) >

Can you divide?

- la consoleLv 79 months ago
volume = surface area * deep

deep = volume / surface area → given that the volume is: 1.3 times 10^(5) m³

deep = [1.3 * 10^(5)] / surface area → where the surface area is: 6.84 times 10^(14) m²

deep = [1.3 * 10^(5)] / [6.84 * 10^(14)]

deep = (1.3/6.84) * [10^(5)/10^(14)]

deep = (1.3/6.84) * [10^(5) * 10^(- 14)]

deep = (1.3/6.84) * 10^(5 - 14)

deep = (1.3/6.84) * 10^(- 9)

deep ≈ 0.19005848 * 10^(- 9) → rounded

deep ≈ 0.19006 * 10^(- 9) ← these are meters

deep ≈ 0.19006 nm ← these are nano-meters

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- RealProLv 79 months ago
You've been recently or at some point in your life introduced to exponents?

You recognize the numbers given as having to do with exponents?

1.3×10^5

-------------

6.83×10^14

(1.3 / 6.84) × 10^(5-14)

0.1903×10^-9

1.901×10^-10

In accordance with precision of input data, we round the answer to 1.9×10^-10 m but you can make it thousandths if you really so desire.

For more practice search "scientific notation" and afterwards make sure you know how to use your calculator.

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- Steve ALv 79 months ago
1.3 x 10^5 / (6.84 x 10^14)

13 x 10^4 / (6.84 x 10^14)

1.90058 x 10^(-10)

I would round to 1.9 x 10^(-10) because of significant digits rule.

To thousandths as requested, 1.901 x 10^(-10)

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- billrussell42Lv 79 months ago
depth = volume/area = 1.3e5 m³ / 6.84e14 m² = 1.901e-10 m

- ...Show all comments
that is a decimal value. Perhaps you mean in a different format?

1.901e-10 m = 1.901x10^-10 m

but surely you could have done this yourself?- Login to reply the answers

Suck my ***.