Finding the Third Proportional to 131,398 and 287,990

Step by Step Solution

1. Step 1: Write the proportion equation
   131,398 : 287,990 = 287,990 : x
2. Step 2: Convert to fraction form
   131,398/287,990 = 287,990/x
3. Step 3: Cross multiply
   131,398x = 287,990 × 287,990
4. Step 4: Simplify right side
   131,398x = 82,938,240,100
5. Step 5: Solve for x
   x = 82,938,240,100/131,398
6. Step 6: Final answer
   x = 631,198.65