Finding the Fourth Proportional to 309,766.64, 427,608.96 and 209,300.72

Step by Step Solution

1. Step 1: Write the proportion equation
   309,766.64 : 427,608.96 = 209,300.72 : x
2. Step 2: Convert to fraction form
   309,766.64/427,608.96 = 209,300.72/x
3. Step 3: Cross multiply
   309,766.64x = 427,608.96 × 209,300.72
4. Step 4: Simplify right side
   309,766.64x = 89,498,863,206.45
5. Step 5: Solve for x
   x = 89,498,863,206.45/309,766.64
6. Step 6: Final answer
   x = 288,923.50