Finding the Fourth Proportional to 290,086.72, 435,171.60 and 128,161.12

Step by Step Solution

1. Step 1: Write the proportion equation
   290,086.72 : 435,171.60 = 128,161.12 : x
2. Step 2: Convert to fraction form
   290,086.72/435,171.60 = 128,161.12/x
3. Step 3: Cross multiply
   290,086.72x = 435,171.60 × 128,161.12
4. Step 4: Simplify right side
   290,086.72x = 55,772,079,648.19
5. Step 5: Solve for x
   x = 55,772,079,648.19/290,086.72
6. Step 6: Final answer
   x = 192,260.02