Finding the Fourth Proportional to 10,886.40, 16,311.68 and 9,978.56

Step by Step Solution

1. Step 1: Write the proportion equation
   10,886.40 : 16,311.68 = 9,978.56 : x
2. Step 2: Convert to fraction form
   10,886.40/16,311.68 = 9,978.56/x
3. Step 3: Cross multiply
   10,886.40x = 16,311.68 × 9,978.56
4. Step 4: Simplify right side
   10,886.40x = 162,767,077.58
5. Step 5: Solve for x
   x = 162,767,077.58/10,886.40
6. Step 6: Final answer
   x = 14,951.41