Finding the Third Proportional to 138,880 and 298,856

Step by Step Solution

1. Step 1: Write the proportion equation
   138,880 : 298,856 = 298,856 : x
2. Step 2: Convert to fraction form
   138,880/298,856 = 298,856/x
3. Step 3: Cross multiply
   138,880x = 298,856 × 298,856
4. Step 4: Simplify right side
   138,880x = 89,314,908,736
5. Step 5: Solve for x
   x = 89,314,908,736/138,880
6. Step 6: Final answer
   x = 643,108.50