Finding the Fourth Proportional to 12,985.76, 17,920.35 and 7,680.93

Step by Step Solution

1. Step 1: Write the proportion equation
   12,985.76 : 17,920.35 = 7,680.93 : x
2. Step 2: Convert to fraction form
   12,985.76/17,920.35 = 7,680.93/x
3. Step 3: Cross multiply
   12,985.76x = 17,920.35 × 7,680.93
4. Step 4: Simplify right side
   12,985.76x = 137,644,953.93
5. Step 5: Solve for x
   x = 137,644,953.93/12,985.76
6. Step 6: Final answer
   x = 10,599.69