Finding the Third Proportional to 287,409 and 435,090

Step by Step Solution

1. Step 1: Write the proportion equation
   287,409 : 435,090 = 435,090 : x
2. Step 2: Convert to fraction form
   287,409/435,090 = 435,090/x
3. Step 3: Cross multiply
   287,409x = 435,090 × 435,090
4. Step 4: Simplify right side
   287,409x = 189,303,308,100
5. Step 5: Solve for x
   x = 189,303,308,100/287,409
6. Step 6: Final answer
   x = 658,654.77