Finding the Fourth Proportional to 30,640.78, 42,284.73 and 18,702.50

Step by Step Solution

1. Step 1: Write the proportion equation
   30,640.78 : 42,284.73 = 18,702.50 : x
2. Step 2: Convert to fraction form
   30,640.78/42,284.73 = 18,702.50/x
3. Step 3: Cross multiply
   30,640.78x = 42,284.73 × 18,702.50
4. Step 4: Simplify right side
   30,640.78x = 790,830,021.54
5. Step 5: Solve for x
   x = 790,830,021.54/30,640.78
6. Step 6: Final answer
   x = 25,809.72