Finding the Fourth Proportional to 30,619.78, 42,259.92 and 18,690.05

Step by Step Solution

1. Step 1: Write the proportion equation
   30,619.78 : 42,259.92 = 18,690.05 : x
2. Step 2: Convert to fraction form
   30,619.78/42,259.92 = 18,690.05/x
3. Step 3: Cross multiply
   30,619.78x = 42,259.92 × 18,690.05
4. Step 4: Simplify right side
   30,619.78x = 789,840,017.80
5. Step 5: Solve for x
   x = 789,840,017.80/30,619.78
6. Step 6: Final answer
   x = 25,795.09