Finding the Third Proportional to 139,258 and 285,890

Step by Step Solution

1. Step 1: Write the proportion equation
   139,258 : 285,890 = 285,890 : x
2. Step 2: Convert to fraction form
   139,258/285,890 = 285,890/x
3. Step 3: Cross multiply
   139,258x = 285,890 × 285,890
4. Step 4: Simplify right side
   139,258x = 81,733,092,100
5. Step 5: Solve for x
   x = 81,733,092,100/139,258
6. Step 6: Final answer
   x = 586,918.47