Finding the Fourth Proportional to 12,781.12, 17,637.72 and 7,813.12

Step by Step Solution

1. Step 1: Write the proportion equation
   12,781.12 : 17,637.72 = 7,813.12 : x
2. Step 2: Convert to fraction form
   12,781.12/17,637.72 = 7,813.12/x
3. Step 3: Cross multiply
   12,781.12x = 17,637.72 × 7,813.12
4. Step 4: Simplify right side
   12,781.12x = 137,805,622.89
5. Step 5: Solve for x
   x = 137,805,622.89/12,781.12
6. Step 6: Final answer
   x = 10,781.97