إن شاء أخذها بحصتها من الثمن وإن شاء تركها
Translation: The buyer may take it for its proportional share of the price, or leave the sale.
If 100 cubits cost 100 dirhams at an explicit one dirham each, and only 90 are found, the buyer may:
1. Take the 90 cubits for 90 dirhams, or
2. Decline the sale.
If the same identified land had merely been sold as “100 cubits for a lump sum of 100,” proportionate price would not automatically follow. The explicit unit-price clause changes the analysis.