Finding the Third Proportional to 558 and 1,388.25

Step by Step Solution

1. Step 1: Write the proportion equation
   558 : 1,388.25 = 1,388.25 : x
2. Step 2: Convert to fraction form
   558/1,388.25 = 1,388.25/x
3. Step 3: Cross multiply
   558x = 1,388.25 × 1,388.25
4. Step 4: Simplify right side
   558x = 1,927,238.06
5. Step 5: Solve for x
   x = 1,927,238.06/558
6. Step 6: Final answer
   x = 3,453.83