Finding the Fourth Proportional to 377,821, 521,393 and 208,054.72

Step by Step Solution

1. Step 1: Write the proportion equation
   377,821 : 521,393 = 208,054.72 : x
2. Step 2: Convert to fraction form
   377,821/521,393 = 208,054.72/x
3. Step 3: Cross multiply
   377,821x = 521,393 × 208,054.72
4. Step 4: Simplify right side
   377,821x = 108,478,274,624.96
5. Step 5: Solve for x
   x = 108,478,274,624.96/377,821
6. Step 6: Final answer
   x = 287,115.52