Finding the Fourth Proportional to 2,145.89, 3,219.30 and 665.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,145.89 : 3,219.30 = 665.12 : x
2. Step 2: Convert to fraction form
   2,145.89/3,219.30 = 665.12/x
3. Step 3: Cross multiply
   2,145.89x = 3,219.30 × 665.12
4. Step 4: Simplify right side
   2,145.89x = 2,141,204.72
5. Step 5: Solve for x
   x = 2,141,204.72/2,145.89
6. Step 6: Final answer
   x = 997.82