That's useful, thanks. The pie chart is attempting to show what proportion of the total costs (i.e. production costs + marketing costs + distribution costs + sales commissions) are attributable to each of those component costs. The fact that the pie chart is expressed in percentage terms gives that away.
As most of the costs are defined relative to the production costs, let's assign a random value of £100 to those costs (doing so just makes things easier, in my view). If the production costs were £100, then the marketing costs would be £30 (i.e. 30% of £100), the distribution costs would be £50 (i.e. 50% of £100) and the sales commissions would be £20 (i.e. 20% of £100). The total costs (i.e. for all four component costs - the whole pie) is therefore £100 + £30 + £50 + £20 = £200. Agreed? So, what proportion of the total pie chart (i.e. of £200) do the production costs (which we assigned a arbitrary value of £100) represent?
My assumption is that as you manipulate that chart (to change the size of the blue production section), the others will automatically resize. But they might not; you might need to resize those too.