Finding the Third Proportional to 138,618 and 291,721.50

Step by Step Solution

1. Step 1: Write the proportion equation
   138,618 : 291,721.50 = 291,721.50 : x
2. Step 2: Convert to fraction form
   138,618/291,721.50 = 291,721.50/x
3. Step 3: Cross multiply
   138,618x = 291,721.50 × 291,721.50
4. Step 4: Simplify right side
   138,618x = 85,101,433,562.25
5. Step 5: Solve for x
   x = 85,101,433,562.25/138,618
6. Step 6: Final answer
   x = 613,927.73