Finding the Fourth Proportional to 42,139.12, 63,156.02 and 21,085.18

Step by Step Solution

1. Step 1: Write the proportion equation
   42,139.12 : 63,156.02 = 21,085.18 : x
2. Step 2: Convert to fraction form
   42,139.12/63,156.02 = 21,085.18/x
3. Step 3: Cross multiply
   42,139.12x = 63,156.02 × 21,085.18
4. Step 4: Simplify right side
   42,139.12x = 1,331,656,049.78
5. Step 5: Solve for x
   x = 1,331,656,049.78/42,139.12
6. Step 6: Final answer
   x = 31,601.42