Finding the Fourth Proportional to 12,983.79, 17,921.30 and 7,680.45

Step by Step Solution

1. Step 1: Write the proportion equation
   12,983.79 : 17,921.30 = 7,680.45 : x
2. Step 2: Convert to fraction form
   12,983.79/17,921.30 = 7,680.45/x
3. Step 3: Cross multiply
   12,983.79x = 17,921.30 × 7,680.45
4. Step 4: Simplify right side
   12,983.79x = 137,643,648.59
5. Step 5: Solve for x
   x = 137,643,648.59/12,983.79
6. Step 6: Final answer
   x = 10,601.19