Finding the Fourth Proportional to 9,388.95, 12,956.22 and 5,139.21

Step by Step Solution

1. Step 1: Write the proportion equation
   9,388.95 : 12,956.22 = 5,139.21 : x
2. Step 2: Convert to fraction form
   9,388.95/12,956.22 = 5,139.21/x
3. Step 3: Cross multiply
   9,388.95x = 12,956.22 × 5,139.21
4. Step 4: Simplify right side
   9,388.95x = 66,584,735.39
5. Step 5: Solve for x
   x = 66,584,735.39/9,388.95
6. Step 6: Final answer
   x = 7,091.82