Finding the Third Proportional to 386,220 and 577,135.50

Step by Step Solution

1. Step 1: Write the proportion equation
   386,220 : 577,135.50 = 577,135.50 : x
2. Step 2: Convert to fraction form
   386,220/577,135.50 = 577,135.50/x
3. Step 3: Cross multiply
   386,220x = 577,135.50 × 577,135.50
4. Step 4: Simplify right side
   386,220x = 333,085,385,360.25
5. Step 5: Solve for x
   x = 333,085,385,360.25/386,220
6. Step 6: Final answer
   x = 862,423.97