Finding the Fourth Proportional to 30,531.58, 42,139.73 and 20,866.84

Step by Step Solution

1. Step 1: Write the proportion equation
   30,531.58 : 42,139.73 = 20,866.84 : x
2. Step 2: Convert to fraction form
   30,531.58/42,139.73 = 20,866.84/x
3. Step 3: Cross multiply
   30,531.58x = 42,139.73 × 20,866.84
4. Step 4: Simplify right side
   30,531.58x = 879,323,003.55
5. Step 5: Solve for x
   x = 879,323,003.55/30,531.58
6. Step 6: Final answer
   x = 28,800.44