Finding the Fourth Proportional to 12,945.78, 17,865.57 and 7,645.14

Step by Step Solution

1. Step 1: Write the proportion equation
   12,945.78 : 17,865.57 = 7,645.14 : x
2. Step 2: Convert to fraction form
   12,945.78/17,865.57 = 7,645.14/x
3. Step 3: Cross multiply
   12,945.78x = 17,865.57 × 7,645.14
4. Step 4: Simplify right side
   12,945.78x = 136,584,783.83
5. Step 5: Solve for x
   x = 136,584,783.83/12,945.78
6. Step 6: Final answer
   x = 10,550.53