Finding the Fourth Proportional to 390,196.50, 538,471.17 and 211,348.50

Step by Step Solution

1. Step 1: Write the proportion equation
   390,196.50 : 538,471.17 = 211,348.50 : x
2. Step 2: Convert to fraction form
   390,196.50/538,471.17 = 211,348.50/x
3. Step 3: Cross multiply
   390,196.50x = 538,471.17 × 211,348.50
4. Step 4: Simplify right side
   390,196.50x = 113,805,074,072.75
5. Step 5: Solve for x
   x = 113,805,074,072.75/390,196.50
6. Step 6: Final answer
   x = 291,660.93