Finding the Fourth Proportional to 1,665.57, 2,495.55 and 842.13

Step by Step Solution

1. Step 1: Write the proportion equation
   1,665.57 : 2,495.55 = 842.13 : x
2. Step 2: Convert to fraction form
   1,665.57/2,495.55 = 842.13/x
3. Step 3: Cross multiply
   1,665.57x = 2,495.55 × 842.13
4. Step 4: Simplify right side
   1,665.57x = 2,101,577.52
5. Step 5: Solve for x
   x = 2,101,577.52/1,665.57
6. Step 6: Final answer
   x = 1,261.78