Finding the Fourth Proportional to 9,978.88, 14,971 and 8,890.72

Step by Step Solution

1. Step 1: Write the proportion equation
   9,978.88 : 14,971 = 8,890.72 : x
2. Step 2: Convert to fraction form
   9,978.88/14,971 = 8,890.72/x
3. Step 3: Cross multiply
   9,978.88x = 14,971 × 8,890.72
4. Step 4: Simplify right side
   9,978.88x = 133,102,969.12
5. Step 5: Solve for x
   x = 133,102,969.12/9,978.88
6. Step 6: Final answer
   x = 13,338.47