Finding the Third Proportional to 1,428.38 and 2,157.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.38 : 2,157.78 = 2,157.78 : x
2. Step 2: Convert to fraction form
   1,428.38/2,157.78 = 2,157.78/x
3. Step 3: Cross multiply
   1,428.38x = 2,157.78 × 2,157.78
4. Step 4: Simplify right side
   1,428.38x = 4,656,019.92
5. Step 5: Solve for x
   x = 4,656,019.92/1,428.38
6. Step 6: Final answer
   x = 3,259.66