Finding the Fourth Proportional to 21,644.91, 29,870.28 and 12,085.74

Step by Step Solution

1. Step 1: Write the proportion equation
   21,644.91 : 29,870.28 = 12,085.74 : x
2. Step 2: Convert to fraction form
   21,644.91/29,870.28 = 12,085.74/x
3. Step 3: Cross multiply
   21,644.91x = 29,870.28 × 12,085.74
4. Step 4: Simplify right side
   21,644.91x = 361,004,437.81
5. Step 5: Solve for x
   x = 361,004,437.81/21,644.91
6. Step 6: Final answer
   x = 16,678.49