Finding the Fourth Proportional to 31,077.29, 42,872.00 and 21,009.26

Step by Step Solution

1. Step 1: Write the proportion equation
   31,077.29 : 42,872.00 = 21,009.26 : x
2. Step 2: Convert to fraction form
   31,077.29/42,872.00 = 21,009.26/x
3. Step 3: Cross multiply
   31,077.29x = 42,872.00 × 21,009.26
4. Step 4: Simplify right side
   31,077.29x = 900,708,675.31
5. Step 5: Solve for x
   x = 900,708,675.31/31,077.29
6. Step 6: Final answer
   x = 28,982.86