If you plant a tree with a DBH of 40-50 cm, according to the formula of 8 times DBH, the soil ball is 320-400cm, but there is no such big specification in the quota. How to set it?

Personally, I think that the planting fee exceeding the fixed soil ball diameter can be calculated by inserting method, that is:

Firstly, according to the calculated diameter of the unearthed ball, subtract the difference of the maximum diameter of the quota, and then divide it by the difference of the maximum diameter of the two gears to get the multiple a;

2. Then, subtract the price of the second largest diameter B from the price of the largest diameter A to get a price difference B;

Third, use A*B to get the price c outside the sizing;

Fourth, use the price of A with the largest diameter, plus B, and the sum is the price of the diameter of the soil ball.