Finding the Fourth Proportional to 31,174.50, 42,986.76 and 21,085.42

Step by Step Solution

1. Step 1: Write the proportion equation
   31,174.50 : 42,986.76 = 21,085.42 : x
2. Step 2: Convert to fraction form
   31,174.50/42,986.76 = 21,085.42/x
3. Step 3: Cross multiply
   31,174.50x = 42,986.76 × 21,085.42
4. Step 4: Simplify right side
   31,174.50x = 906,393,889.04
5. Step 5: Solve for x
   x = 906,393,889.04/31,174.50
6. Step 6: Final answer
   x = 29,074.85