Finding the Fourth Proportional to 9,319.72, 12,861.32 and 5,128

Step by Step Solution

1. Step 1: Write the proportion equation
   9,319.72 : 12,861.32 = 5,128 : x
2. Step 2: Convert to fraction form
   9,319.72/12,861.32 = 5,128/x
3. Step 3: Cross multiply
   9,319.72x = 12,861.32 × 5,128
4. Step 4: Simplify right side
   9,319.72x = 65,952,848.96
5. Step 5: Solve for x
   x = 65,952,848.96/9,319.72
6. Step 6: Final answer
   x = 7,076.70