Finding the Fourth Proportional to 21,139.18, 31,689.15 and 7,804.81

Step by Step Solution

1. Step 1: Write the proportion equation
   21,139.18 : 31,689.15 = 7,804.81 : x
2. Step 2: Convert to fraction form
   21,139.18/31,689.15 = 7,804.81/x
3. Step 3: Cross multiply
   21,139.18x = 31,689.15 × 7,804.81
4. Step 4: Simplify right side
   21,139.18x = 247,327,636.37
5. Step 5: Solve for x
   x = 247,327,636.37/21,139.18
6. Step 6: Final answer
   x = 11,699.97