The price of the diamond is directly proportional to the square of its weight:
\[ P = k \times W^2 \]
Given the price of the 10-gram diamond is Rs. 2,00,000:
\[ 2,00,000 = k \times 10^2 \] \[ k = \frac{2,00,000}{100} = 2000 \]
Total price after breaking the diamond:
\[ Total \ Price = 50,000 + 18,000 + 8,000 = 76,000 \]
The trader bought the diamond for Rs. 2,00,000 and sold the pieces for Rs. 76,000. The total loss is:
\[ Loss = 2,00,000 - 76,000 = 1,24,000 \]
The total loss incurred by the trader is Rs. 1,24,000.