Finding the Fourth Proportional to 1,378.69, 1,902.18 and 818.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,378.69 : 1,902.18 = 818.88 : x
2. Step 2: Convert to fraction form
   1,378.69/1,902.18 = 818.88/x
3. Step 3: Cross multiply
   1,378.69x = 1,902.18 × 818.88
4. Step 4: Simplify right side
   1,378.69x = 1,557,653.10
5. Step 5: Solve for x
   x = 1,557,653.10/1,378.69
6. Step 6: Final answer
   x = 1,129.81