Finding the Fourth Proportional to 9,156.54, 12,636.90 and 5,571.21

Step by Step Solution

1. Step 1: Write the proportion equation
   9,156.54 : 12,636.90 = 5,571.21 : x
2. Step 2: Convert to fraction form
   9,156.54/12,636.90 = 5,571.21/x
3. Step 3: Cross multiply
   9,156.54x = 12,636.90 × 5,571.21
4. Step 4: Simplify right side
   9,156.54x = 70,402,823.65
5. Step 5: Solve for x
   x = 70,402,823.65/9,156.54
6. Step 6: Final answer
   x = 7,688.80