Finding the Fourth Proportional to 30,670.61, 42,400.92 and 30,389.94

Step by Step Solution

1. Step 1: Write the proportion equation
   30,670.61 : 42,400.92 = 30,389.94 : x
2. Step 2: Convert to fraction form
   30,670.61/42,400.92 = 30,389.94/x
3. Step 3: Cross multiply
   30,670.61x = 42,400.92 × 30,389.94
4. Step 4: Simplify right side
   30,670.61x = 1,288,561,414.74
5. Step 5: Solve for x
   x = 1,288,561,414.74/30,670.61
6. Step 6: Final answer
   x = 42,012.91