Finding the Fourth Proportional to 21,405.20, 32,268.23 and 19,978

Step by Step Solution

1. Step 1: Write the proportion equation
   21,405.20 : 32,268.23 = 19,978 : x
2. Step 2: Convert to fraction form
   21,405.20/32,268.23 = 19,978/x
3. Step 3: Cross multiply
   21,405.20x = 32,268.23 × 19,978
4. Step 4: Simplify right side
   21,405.20x = 644,654,698.94
5. Step 5: Solve for x
   x = 644,654,698.94/21,405.20
6. Step 6: Final answer
   x = 30,116.73