Finding the Fourth Proportional to 7,779.57, 10,665.89 and 7,639.46

Step by Step Solution

1. Step 1: Write the proportion equation
   7,779.57 : 10,665.89 = 7,639.46 : x
2. Step 2: Convert to fraction form
   7,779.57/10,665.89 = 7,639.46/x
3. Step 3: Cross multiply
   7,779.57x = 10,665.89 × 7,639.46
4. Step 4: Simplify right side
   7,779.57x = 81,481,640.02
5. Step 5: Solve for x
   x = 81,481,640.02/7,779.57
6. Step 6: Final answer
   x = 10,473.80