Finding the Fourth Proportional to 72,235.68, 99,684.72 and 42,021.60

Step by Step Solution

1. Step 1: Write the proportion equation
   72,235.68 : 99,684.72 = 42,021.60 : x
2. Step 2: Convert to fraction form
   72,235.68/99,684.72 = 42,021.60/x
3. Step 3: Cross multiply
   72,235.68x = 99,684.72 × 42,021.60
4. Step 4: Simplify right side
   72,235.68x = 4,188,911,429.95
5. Step 5: Solve for x
   x = 4,188,911,429.95/72,235.68
6. Step 6: Final answer
   x = 57,989.51