Finding the Fourth Proportional to 21,765.48, 30,020.78 and 19,978.62

Step by Step Solution

1. Step 1: Write the proportion equation
   21,765.48 : 30,020.78 = 19,978.62 : x
2. Step 2: Convert to fraction form
   21,765.48/30,020.78 = 19,978.62/x
3. Step 3: Cross multiply
   21,765.48x = 30,020.78 × 19,978.62
4. Step 4: Simplify right side
   21,765.48x = 599,773,755.72
5. Step 5: Solve for x
   x = 599,773,755.72/21,765.48
6. Step 6: Final answer
   x = 27,556.19