Finding the Fourth Proportional to 1,085.12, 1,626.12 and 840.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,085.12 : 1,626.12 = 840.50 : x
2. Step 2: Convert to fraction form
   1,085.12/1,626.12 = 840.50/x
3. Step 3: Cross multiply
   1,085.12x = 1,626.12 × 840.50
4. Step 4: Simplify right side
   1,085.12x = 1,366,753.86
5. Step 5: Solve for x
   x = 1,366,753.86/1,085.12
6. Step 6: Final answer
   x = 1,259.54