Finding the Third Proportional to 187,688 and 390,856

Step by Step Solution

1. Step 1: Write the proportion equation
   187,688 : 390,856 = 390,856 : x
2. Step 2: Convert to fraction form
   187,688/390,856 = 390,856/x
3. Step 3: Cross multiply
   187,688x = 390,856 × 390,856
4. Step 4: Simplify right side
   187,688x = 152,768,412,736
5. Step 5: Solve for x
   x = 152,768,412,736/187,688
6. Step 6: Final answer
   x = 813,948.75