Finding the Fourth Proportional to 31,143.85, 42,965.43 and 21,717.88

Step by Step Solution

1. Step 1: Write the proportion equation
   31,143.85 : 42,965.43 = 21,717.88 : x
2. Step 2: Convert to fraction form
   31,143.85/42,965.43 = 21,717.88/x
3. Step 3: Cross multiply
   31,143.85x = 42,965.43 × 21,717.88
4. Step 4: Simplify right side
   31,143.85x = 933,118,052.89
5. Step 5: Solve for x
   x = 933,118,052.89/31,143.85
6. Step 6: Final answer
   x = 29,961.55