Finding the Fourth Proportional to 12,947.33, 17,866.62 and 7,640.21

Step by Step Solution

1. Step 1: Write the proportion equation
   12,947.33 : 17,866.62 = 7,640.21 : x
2. Step 2: Convert to fraction form
   12,947.33/17,866.62 = 7,640.21/x
3. Step 3: Cross multiply
   12,947.33x = 17,866.62 × 7,640.21
4. Step 4: Simplify right side
   12,947.33x = 136,504,639.46
5. Step 5: Solve for x
   x = 136,504,639.46/12,947.33
6. Step 6: Final answer
   x = 10,543.08