Finding the Fourth Proportional to 1,091.89, 1,638.52 and 442.63

Step by Step Solution

1. Step 1: Write the proportion equation
   1,091.89 : 1,638.52 = 442.63 : x
2. Step 2: Convert to fraction form
   1,091.89/1,638.52 = 442.63/x
3. Step 3: Cross multiply
   1,091.89x = 1,638.52 × 442.63
4. Step 4: Simplify right side
   1,091.89x = 725,254.56
5. Step 5: Solve for x
   x = 725,254.56/1,091.89
6. Step 6: Final answer
   x = 664.22