Finding the Fourth Proportional to 12,938.90, 17,855.12 and 7,911.52

Step by Step Solution

1. Step 1: Write the proportion equation
   12,938.90 : 17,855.12 = 7,911.52 : x
2. Step 2: Convert to fraction form
   12,938.90/17,855.12 = 7,911.52/x
3. Step 3: Cross multiply
   12,938.90x = 17,855.12 × 7,911.52
4. Step 4: Simplify right side
   12,938.90x = 141,261,114.12
5. Step 5: Solve for x
   x = 141,261,114.12/12,938.90
6. Step 6: Final answer
   x = 10,917.56