Finding the Fourth Proportional to 9,990.86, 13,787.33 and 5,453.55

Step by Step Solution

1. Step 1: Write the proportion equation
   9,990.86 : 13,787.33 = 5,453.55 : x
2. Step 2: Convert to fraction form
   9,990.86/13,787.33 = 5,453.55/x
3. Step 3: Cross multiply
   9,990.86x = 13,787.33 × 5,453.55
4. Step 4: Simplify right side
   9,990.86x = 75,189,866.25
5. Step 5: Solve for x
   x = 75,189,866.25/9,990.86
6. Step 6: Final answer
   x = 7,525.87