Finding the Fourth Proportional to 1,016.67, 1,400.94 and 780.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,016.67 : 1,400.94 = 780.60 : x
2. Step 2: Convert to fraction form
   1,016.67/1,400.94 = 780.60/x
3. Step 3: Cross multiply
   1,016.67x = 1,400.94 × 780.60
4. Step 4: Simplify right side
   1,016.67x = 1,093,573.76
5. Step 5: Solve for x
   x = 1,093,573.76/1,016.67
6. Step 6: Final answer
   x = 1,075.64