Finding the Fourth Proportional to 21,279.12, 31,907.34 and 8,123.94

Step by Step Solution

1. Step 1: Write the proportion equation
   21,279.12 : 31,907.34 = 8,123.94 : x
2. Step 2: Convert to fraction form
   21,279.12/31,907.34 = 8,123.94/x
3. Step 3: Cross multiply
   21,279.12x = 31,907.34 × 8,123.94
4. Step 4: Simplify right side
   21,279.12x = 259,213,315.72
5. Step 5: Solve for x
   x = 259,213,315.72/21,279.12
6. Step 6: Final answer
   x = 12,181.58