Finding the Fourth Proportional to 13,809.20, 19,056.90 and 7,521.57

Step by Step Solution

1. Step 1: Write the proportion equation
   13,809.20 : 19,056.90 = 7,521.57 : x
2. Step 2: Convert to fraction form
   13,809.20/19,056.90 = 7,521.57/x
3. Step 3: Cross multiply
   13,809.20x = 19,056.90 × 7,521.57
4. Step 4: Simplify right side
   13,809.20x = 143,337,807.33
5. Step 5: Solve for x
   x = 143,337,807.33/13,809.20
6. Step 6: Final answer
   x = 10,379.88