Finding the Fourth Proportional to 1,091.91, 1,636.95 and 443.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,091.91 : 1,636.95 = 443.10 : x
2. Step 2: Convert to fraction form
   1,091.91/1,636.95 = 443.10/x
3. Step 3: Cross multiply
   1,091.91x = 1,636.95 × 443.10
4. Step 4: Simplify right side
   1,091.91x = 725,332.55
5. Step 5: Solve for x
   x = 725,332.55/1,091.91
6. Step 6: Final answer
   x = 664.28