Finding the Fourth Proportional to 1,085.72, 1,498.65 and 660.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,085.72 : 1,498.65 = 660.34 : x
2. Step 2: Convert to fraction form
   1,085.72/1,498.65 = 660.34/x
3. Step 3: Cross multiply
   1,085.72x = 1,498.65 × 660.34
4. Step 4: Simplify right side
   1,085.72x = 989,625.87
5. Step 5: Solve for x
   x = 989,625.87/1,085.72
6. Step 6: Final answer
   x = 911.49