Finding the Fourth Proportional to 12,810.83, 17,678.99 and 7,145.55

Step by Step Solution

1. Step 1: Write the proportion equation
   12,810.83 : 17,678.99 = 7,145.55 : x
2. Step 2: Convert to fraction form
   12,810.83/17,678.99 = 7,145.55/x
3. Step 3: Cross multiply
   12,810.83x = 17,678.99 × 7,145.55
4. Step 4: Simplify right side
   12,810.83x = 126,326,124.86
5. Step 5: Solve for x
   x = 126,326,124.86/12,810.83
6. Step 6: Final answer
   x = 9,860.89