Finding the Fourth Proportional to 1,662.12, 2,491.56 and 840.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,662.12 : 2,491.56 = 840.78 : x
2. Step 2: Convert to fraction form
   1,662.12/2,491.56 = 840.78/x
3. Step 3: Cross multiply
   1,662.12x = 2,491.56 × 840.78
4. Step 4: Simplify right side
   1,662.12x = 2,094,853.82
5. Step 5: Solve for x
   x = 2,094,853.82/1,662.12
6. Step 6: Final answer
   x = 1,260.35