Finding the Fourth Proportional to 1,203.78, 1,662.59 and 810.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,203.78 : 1,662.59 = 810.12 : x
2. Step 2: Convert to fraction form
   1,203.78/1,662.59 = 810.12/x
3. Step 3: Cross multiply
   1,203.78x = 1,662.59 × 810.12
4. Step 4: Simplify right side
   1,203.78x = 1,346,895.39
5. Step 5: Solve for x
   x = 1,346,895.39/1,203.78
6. Step 6: Final answer
   x = 1,118.89