Finding the Fourth Proportional to 2,420.72, 3,630.78 and 665.85

Step by Step Solution

1. Step 1: Write the proportion equation
   2,420.72 : 3,630.78 = 665.85 : x
2. Step 2: Convert to fraction form
   2,420.72/3,630.78 = 665.85/x
3. Step 3: Cross multiply
   2,420.72x = 3,630.78 × 665.85
4. Step 4: Simplify right side
   2,420.72x = 2,417,554.86
5. Step 5: Solve for x
   x = 2,417,554.86/2,420.72
6. Step 6: Final answer
   x = 998.69