Finding the Fourth Proportional to 428,686.84, 643,004.34 and 191,965.96

Step by Step Solution

1. Step 1: Write the proportion equation
   428,686.84 : 643,004.34 = 191,965.96 : x
2. Step 2: Convert to fraction form
   428,686.84/643,004.34 = 191,965.96/x
3. Step 3: Cross multiply
   428,686.84x = 643,004.34 × 191,965.96
4. Step 4: Simplify right side
   428,686.84x = 123,434,945,412.27
5. Step 5: Solve for x
   x = 123,434,945,412.27/428,686.84
6. Step 6: Final answer
   x = 287,937.33