Finding the Fourth Proportional to 1,085.59, 1,498.26 and 665.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,085.59 : 1,498.26 = 665.86 : x
2. Step 2: Convert to fraction form
   1,085.59/1,498.26 = 665.86/x
3. Step 3: Cross multiply
   1,085.59x = 1,498.26 × 665.86
4. Step 4: Simplify right side
   1,085.59x = 997,631.40
5. Step 5: Solve for x
   x = 997,631.40/1,085.59
6. Step 6: Final answer
   x = 918.98