Finding the Fourth Proportional to 12,987.95, 17,921.09 and 7,680.83

Step by Step Solution

1. Step 1: Write the proportion equation
   12,987.95 : 17,921.09 = 7,680.83 : x
2. Step 2: Convert to fraction form
   12,987.95/17,921.09 = 7,680.83/x
3. Step 3: Cross multiply
   12,987.95x = 17,921.09 × 7,680.83
4. Step 4: Simplify right side
   12,987.95x = 137,648,845.70
5. Step 5: Solve for x
   x = 137,648,845.70/12,987.95
6. Step 6: Final answer
   x = 10,598.20