Finding the Third Proportional to 1,888.31 and 3,991.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,888.31 : 3,991.78 = 3,991.78 : x
2. Step 2: Convert to fraction form
   1,888.31/3,991.78 = 3,991.78/x
3. Step 3: Cross multiply
   1,888.31x = 3,991.78 × 3,991.78
4. Step 4: Simplify right side
   1,888.31x = 15,934,317.55
5. Step 5: Solve for x
   x = 15,934,317.55/1,888.31
6. Step 6: Final answer
   x = 8,438.39