If the total number of earthquakes annually averages 14,500 approximately how many are magnitude 5 or higher? and show work.

To take a percentage of a number out, simply do the follow:

Number x Percentage = Answer.

Therefore:

14,500x (90/100) = 13,050

To find what percentage a figure represents of a total, do the following simple equation:

Figure/Total x100 = Percentage.

So for your Earthquakes, you have a total of:

Total = 90 + 20 + 5 + 1 = 116 Earthquakes.

4 to 5 - > 90/116 x100 = 78% to 2 sig. fig.

5 to 6 - > 20/116 x100 = 17%

6 to 7 - > 5/116 x100 = 4%

7 + - > 1/116 x100 = 1%

The same technique is used everywhere else, sample size divided by total multiplied by 100 gives percentage. Not multiplying by 100 gives you a ratio of 1 that it represents, 1 being 100% (a complete unit).

Therefore for part 1. of your question I would just do 14,500x0.9=13,050.

You'll probably see that 90/100 = 0.9 since 90% is identical to writing 90/100 or 0.9.