Finding the Fourth Proportional to 1,139.39, 1,570.29 and 785.33

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.39 : 1,570.29 = 785.33 : x
2. Step 2: Convert to fraction form
   1,139.39/1,570.29 = 785.33/x
3. Step 3: Cross multiply
   1,139.39x = 1,570.29 × 785.33
4. Step 4: Simplify right side
   1,139.39x = 1,233,195.85
5. Step 5: Solve for x
   x = 1,233,195.85/1,139.39
6. Step 6: Final answer
   x = 1,082.33