Finding the Fourth Proportional to 1,138.78, 1,570.56 and 807.08

Step by Step Solution

1. Step 1: Write the proportion equation
   1,138.78 : 1,570.56 = 807.08 : x
2. Step 2: Convert to fraction form
   1,138.78/1,570.56 = 807.08/x
3. Step 3: Cross multiply
   1,138.78x = 1,570.56 × 807.08
4. Step 4: Simplify right side
   1,138.78x = 1,267,567.56
5. Step 5: Solve for x
   x = 1,267,567.56/1,138.78
6. Step 6: Final answer
   x = 1,113.09