Finding the Third Proportional to 275,608.50 and 390,090

Step by Step Solution

1. Step 1: Write the proportion equation
   275,608.50 : 390,090 = 390,090 : x
2. Step 2: Convert to fraction form
   275,608.50/390,090 = 390,090/x
3. Step 3: Cross multiply
   275,608.50x = 390,090 × 390,090
4. Step 4: Simplify right side
   275,608.50x = 152,170,208,100
5. Step 5: Solve for x
   x = 152,170,208,100/275,608.50
6. Step 6: Final answer
   x = 552,124.51