The diameter of the Earth is 7926 miles at its equator. The highest point on Earth (Mt. Everest) is 5.5 miles above sea level; the lowest point (Mariana Trench in the Pacific Ocean) is 6.8 miles below sea level. Hence, the "roughness" of the Earth’s surface is 5.5+6.8 = 12.3 miles. What is the ratio of the roughness of the Earth's surface to the Earth’s diameter? Express this ratio to a precision of one decimal place both in scientific notation and as a percentage.

I think I've got the ratio and the percentage correct,I'm not really sure what he's asking me to put in scientific notation?

Question

The diameter of the Earth is 7926 miles at its equator. The highest point on Earth (Mt. Everest) is 5.5 miles above sea level; the lowest point (Mariana Trench in the Pacific Ocean) is 6.8 miles below sea level. Hence, the "roughness" of the Earth’s surface is 5.5+6.8 = 12.3 miles. What is the ratio of the roughness of the Earth's surface to the Earth’s diameter? Express this ratio to a precision of one decimal place both in scientific notation and as a percentage.

I think I've got the ratio and the percentage correct,I'm not really sure what he's asking me to put in scientific notation?

akashdeepdeb · Answer

Precision should be to ONE DECIMAL PLACE...
He is asking you to round it off to one decimal place...

What is the ration, Tell me what you got. :D

anonymous · Answer

The ratio starts as 12.3:7926. Complete the division and you get 1:644.4. This is equal to 0.2%

akashdeepdeb · Answer

Awesome
So 0.2% means 0.2/100 or 0.002

So in scientific notation anything is written in the form

a * 10^z [Where z is the power of 10]
a is a number between 1 and 10.

So 0.2% is written in scientific notation as
2 * 10^-4


Understood? :)

anonymous · Answer

ahh ok ya that makes sense. I'm pretty confident in calculating all 3, but just brain farted converting them to each other for some reason tonight. Thanks for the explanation!

akashdeepdeb · Answer

:)