Finding the Fourth Proportional to 9,045.18, 12,477.78 and 5,639.40

Step by Step Solution

1. Step 1: Write the proportion equation
   9,045.18 : 12,477.78 = 5,639.40 : x
2. Step 2: Convert to fraction form
   9,045.18/12,477.78 = 5,639.40/x
3. Step 3: Cross multiply
   9,045.18x = 12,477.78 × 5,639.40
4. Step 4: Simplify right side
   9,045.18x = 70,367,192.53
5. Step 5: Solve for x
   x = 70,367,192.53/9,045.18
6. Step 6: Final answer
   x = 7,779.52