Finding the Fourth Proportional to 10,071.78, 13,900.72 and 8,390.52

Step by Step Solution

1. Step 1: Write the proportion equation
   10,071.78 : 13,900.72 = 8,390.52 : x
2. Step 2: Convert to fraction form
   10,071.78/13,900.72 = 8,390.52/x
3. Step 3: Cross multiply
   10,071.78x = 13,900.72 × 8,390.52
4. Step 4: Simplify right side
   10,071.78x = 116,634,269.17
5. Step 5: Solve for x
   x = 116,634,269.17/10,071.78
6. Step 6: Final answer
   x = 11,580.30