Finding the Third Proportional to 5,188.78 and 7,788.38

Step by Step Solution

1. Step 1: Write the proportion equation
   5,188.78 : 7,788.38 = 7,788.38 : x
2. Step 2: Convert to fraction form
   5,188.78/7,788.38 = 7,788.38/x
3. Step 3: Cross multiply
   5,188.78x = 7,788.38 × 7,788.38
4. Step 4: Simplify right side
   5,188.78x = 60,658,785.14
5. Step 5: Solve for x
   x = 60,658,785.14/5,188.78
6. Step 6: Final answer
   x = 11,690.37