Finding the Fourth Proportional to 21,229, 31,619.25 and 20,118.76

Step by Step Solution

1. Step 1: Write the proportion equation
   21,229 : 31,619.25 = 20,118.76 : x
2. Step 2: Convert to fraction form
   21,229/31,619.25 = 20,118.76/x
3. Step 3: Cross multiply
   21,229x = 31,619.25 × 20,118.76
4. Step 4: Simplify right side
   21,229x = 636,140,102.13
5. Step 5: Solve for x
   x = 636,140,102.13/21,229
6. Step 6: Final answer
   x = 29,965.62