Expressing fractions as 100% in excel

[ZeroZero]

Very average maths here. Rusty on Excel, once fairly competent.

I am trying to construct a  simple chart in excel

Here is the data:

Age of the Earth 4.54 (billion years)

Archean Era begins  3.8 

Proterozoic begins 2.5 

Phanerozoic begins 0.57

I am looking to create a sunburst or donut type chart where it shows the eons in segments. 

4.54 would be 360 degrees of the chart.  I term this whole life of the planet" here "whole"

The other numbers would have to be calculated as percentages of the whole

I have two questions please:

1] Which formula can you use to express 4.54 as 100% (not as a fraction of 100% but AS 100% or 'all') 

2] How would one calculate the other fractions so that the chart has the correct sections? 

I am stumped!

 

thanks

 

Zero

[iNow]

I’m rusty, but think you can use age of the earth as your denominator then format the result cell it as a percentage.

So, let’s say you put 4.54 in cell A1. Your age of Earth percentage calculation would just be A1/A1. Then if you had 3.8 for Archean in cell B1, the percentage for that would just be B1/A1. Repeat each calculation with A1 as denominator and highlight the results when making your donut chart. 

[Country Boy]

Taking the age of the earth as 100% each of these other ages would be divided by the age of the earth, 4.54, then multiplied by 100 to give a percent.

For example, the Archean Era would be 3.8/4.54= 0.837 so 83.7%.

Proterozoic would be 2.5/4.54=  0.551 so 55.1%.

Phanerozoic would be 0.57/4.54=  0.126 so 12.6%.