Histogram and cumulative distribution function

I am trying to find the bin number for which the area of cdf of variable X is 25% of total area.

Is there any inbuilt function for this purpose?

How can i implement this ?

Thanks in advance

[Walter Roberson]

What datatype is variable X ? For example did you use makedist() ? https://www.mathworks.com/help/stats/prob.normaldistribution.cdf.html