Finding the Third Proportional to 1,978.50 and 3,921.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.50 : 3,921.38 = 3,921.38 : x
2. Step 2: Convert to fraction form
   1,978.50/3,921.38 = 3,921.38/x
3. Step 3: Cross multiply
   1,978.50x = 3,921.38 × 3,921.38
4. Step 4: Simplify right side
   1,978.50x = 15,377,181.89
5. Step 5: Solve for x
   x = 15,377,181.89/1,978.50
6. Step 6: Final answer
   x = 7,772.14