Finding the Fourth Proportional to 42,391.76, 63,605.60 and 21,320.72

Step by Step Solution

1. Step 1: Write the proportion equation
   42,391.76 : 63,605.60 = 21,320.72 : x
2. Step 2: Convert to fraction form
   42,391.76/63,605.60 = 21,320.72/x
3. Step 3: Cross multiply
   42,391.76x = 63,605.60 × 21,320.72
4. Step 4: Simplify right side
   42,391.76x = 1,356,117,188.03
5. Step 5: Solve for x
   x = 1,356,117,188.03/42,391.76
6. Step 6: Final answer
   x = 31,990.11