Finding the Fourth Proportional to 390,987, 539,562.06 and 212,139

Step by Step Solution

1. Step 1: Write the proportion equation
   390,987 : 539,562.06 = 212,139 : x
2. Step 2: Convert to fraction form
   390,987/539,562.06 = 212,139/x
3. Step 3: Cross multiply
   390,987x = 539,562.06 × 212,139
4. Step 4: Simplify right side
   390,987x = 114,462,155,846.34
5. Step 5: Solve for x
   x = 114,462,155,846.34/390,987
6. Step 6: Final answer
   x = 292,751.82