Finding the Fourth Proportional to 9,978.20, 13,770.84 and 5,729.82

Step by Step Solution

1. Step 1: Write the proportion equation
   9,978.20 : 13,770.84 = 5,729.82 : x
2. Step 2: Convert to fraction form
   9,978.20/13,770.84 = 5,729.82/x
3. Step 3: Cross multiply
   9,978.20x = 13,770.84 × 5,729.82
4. Step 4: Simplify right side
   9,978.20x = 78,904,372.06
5. Step 5: Solve for x
   x = 78,904,372.06/9,978.20
6. Step 6: Final answer
   x = 7,907.68