Finding the Fourth Proportional to 12,810.39, 17,678.43 and 7,145.51

Step by Step Solution

1. Step 1: Write the proportion equation
   12,810.39 : 17,678.43 = 7,145.51 : x
2. Step 2: Convert to fraction form
   12,810.39/17,678.43 = 7,145.51/x
3. Step 3: Cross multiply
   12,810.39x = 17,678.43 × 7,145.51
4. Step 4: Simplify right side
   12,810.39x = 126,321,309.96
5. Step 5: Solve for x
   x = 126,321,309.96/12,810.39
6. Step 6: Final answer
   x = 9,860.85