Finding the Fourth Proportional to 310,502.72, 428,154.72 and 209,725.76

Step by Step Solution

1. Step 1: Write the proportion equation
   310,502.72 : 428,154.72 = 209,725.76 : x
2. Step 2: Convert to fraction form
   310,502.72/428,154.72 = 209,725.76/x
3. Step 3: Cross multiply
   310,502.72x = 428,154.72 × 209,725.76
4. Step 4: Simplify right side
   310,502.72x = 89,795,074,049.59
5. Step 5: Solve for x
   x = 89,795,074,049.59/310,502.72
6. Step 6: Final answer
   x = 289,192.55