Finding the Fourth Proportional to 21,085.94, 31,563.28 and 13,278.34

Step by Step Solution

1. Step 1: Write the proportion equation
   21,085.94 : 31,563.28 = 13,278.34 : x
2. Step 2: Convert to fraction form
   21,085.94/31,563.28 = 13,278.34/x
3. Step 3: Cross multiply
   21,085.94x = 31,563.28 × 13,278.34
4. Step 4: Simplify right side
   21,085.94x = 419,107,963.36
5. Step 5: Solve for x
   x = 419,107,963.36/21,085.94
6. Step 6: Final answer
   x = 19,876.18