Finding the Fourth Proportional to 12,992.47, 17,931.51 and 7,688.99

Step by Step Solution

1. Step 1: Write the proportion equation
   12,992.47 : 17,931.51 = 7,688.99 : x
2. Step 2: Convert to fraction form
   12,992.47/17,931.51 = 7,688.99/x
3. Step 3: Cross multiply
   12,992.47x = 17,931.51 × 7,688.99
4. Step 4: Simplify right side
   12,992.47x = 137,875,245.90
5. Step 5: Solve for x
   x = 137,875,245.90/12,992.47
6. Step 6: Final answer
   x = 10,611.94