Finding the Fourth Proportional to 390,148, 538,404.24 and 211,300

Step by Step Solution

1. Step 1: Write the proportion equation
   390,148 : 538,404.24 = 211,300 : x
2. Step 2: Convert to fraction form
   390,148/538,404.24 = 211,300/x
3. Step 3: Cross multiply
   390,148x = 538,404.24 × 211,300
4. Step 4: Simplify right side
   390,148x = 113,764,815,912
5. Step 5: Solve for x
   x = 113,764,815,912/390,148
6. Step 6: Final answer
   x = 291,594