Finding the Fourth Proportional to 639,439.48, 958,951.56 and 212,860.72

Step by Step Solution

1. Step 1: Write the proportion equation
   639,439.48 : 958,951.56 = 212,860.72 : x
2. Step 2: Convert to fraction form
   639,439.48/958,951.56 = 212,860.72/x
3. Step 3: Cross multiply
   639,439.48x = 958,951.56 × 212,860.72
4. Step 4: Simplify right side
   639,439.48x = 204,123,119,506.72
5. Step 5: Solve for x
   x = 204,123,119,506.72/639,439.48
6. Step 6: Final answer
   x = 319,221.95