Finding the Fourth Proportional to 21,116.43, 31,681.89 and 7,972.56

Step by Step Solution

1. Step 1: Write the proportion equation
   21,116.43 : 31,681.89 = 7,972.56 : x
2. Step 2: Convert to fraction form
   21,116.43/31,681.89 = 7,972.56/x
3. Step 3: Cross multiply
   21,116.43x = 31,681.89 × 7,972.56
4. Step 4: Simplify right side
   21,116.43x = 252,585,768.94
5. Step 5: Solve for x
   x = 252,585,768.94/21,116.43
6. Step 6: Final answer
   x = 11,961.58