Finding the Fourth Proportional to 12,640.02, 17,435.70 and 7,916.10

Step by Step Solution

1. Step 1: Write the proportion equation
   12,640.02 : 17,435.70 = 7,916.10 : x
2. Step 2: Convert to fraction form
   12,640.02/17,435.70 = 7,916.10/x
3. Step 3: Cross multiply
   12,640.02x = 17,435.70 × 7,916.10
4. Step 4: Simplify right side
   12,640.02x = 138,022,744.77
5. Step 5: Solve for x
   x = 138,022,744.77/12,640.02
6. Step 6: Final answer
   x = 10,919.50