Finding the Fourth Proportional to 1,091.30, 1,638.82 and 728.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,091.30 : 1,638.82 = 728.42 : x
2. Step 2: Convert to fraction form
   1,091.30/1,638.82 = 728.42/x
3. Step 3: Cross multiply
   1,091.30x = 1,638.82 × 728.42
4. Step 4: Simplify right side
   1,091.30x = 1,193,749.26
5. Step 5: Solve for x
   x = 1,193,749.26/1,091.30
6. Step 6: Final answer
   x = 1,093.88