Finding the Fourth Proportional to 65,287.52, 90,063.62 and 42,639.78

Step by Step Solution

1. Step 1: Write the proportion equation
   65,287.52 : 90,063.62 = 42,639.78 : x
2. Step 2: Convert to fraction form
   65,287.52/90,063.62 = 42,639.78/x
3. Step 3: Cross multiply
   65,287.52x = 90,063.62 × 42,639.78
4. Step 4: Simplify right side
   65,287.52x = 3,840,292,729.60
5. Step 5: Solve for x
   x = 3,840,292,729.60/65,287.52
6. Step 6: Final answer
   x = 58,821.24