Finding the Fourth Proportional to 1,144.85, 1,716.69 and 815.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,144.85 : 1,716.69 = 815.60 : x
2. Step 2: Convert to fraction form
   1,144.85/1,716.69 = 815.60/x
3. Step 3: Cross multiply
   1,144.85x = 1,716.69 × 815.60
4. Step 4: Simplify right side
   1,144.85x = 1,400,123.78
5. Step 5: Solve for x
   x = 1,400,123.78/1,144.85
6. Step 6: Final answer
   x = 1,222.98