Finding the Fourth Proportional to 2,645.61, 3,968.85 and 890.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,645.61 : 3,968.85 = 890.76 : x
2. Step 2: Convert to fraction form
   2,645.61/3,968.85 = 890.76/x
3. Step 3: Cross multiply
   2,645.61x = 3,968.85 × 890.76
4. Step 4: Simplify right side
   2,645.61x = 3,535,292.83
5. Step 5: Solve for x
   x = 3,535,292.83/2,645.61
6. Step 6: Final answer
   x = 1,336.29