Finding the Fourth Proportional to 31,147.50, 42,987.51 and 20,559.18

Step by Step Solution

1. Step 1: Write the proportion equation
   31,147.50 : 42,987.51 = 20,559.18 : x
2. Step 2: Convert to fraction form
   31,147.50/42,987.51 = 20,559.18/x
3. Step 3: Cross multiply
   31,147.50x = 42,987.51 × 20,559.18
4. Step 4: Simplify right side
   31,147.50x = 883,787,955.84
5. Step 5: Solve for x
   x = 883,787,955.84/31,147.50
6. Step 6: Final answer
   x = 28,374.28