Finding the Fourth Proportional to 30,590.42, 42,229.61 and 20,515.17

Step by Step Solution

1. Step 1: Write the proportion equation
   30,590.42 : 42,229.61 = 20,515.17 : x
2. Step 2: Convert to fraction form
   30,590.42/42,229.61 = 20,515.17/x
3. Step 3: Cross multiply
   30,590.42x = 42,229.61 × 20,515.17
4. Step 4: Simplify right side
   30,590.42x = 866,347,525.61
5. Step 5: Solve for x
   x = 866,347,525.61/30,590.42
6. Step 6: Final answer
   x = 28,320.88