Finding the Fourth Proportional to 1,379.09, 1,903.40 and 819.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.09 : 1,903.40 = 819.89 : x
2. Step 2: Convert to fraction form
   1,379.09/1,903.40 = 819.89/x
3. Step 3: Cross multiply
   1,379.09x = 1,903.40 × 819.89
4. Step 4: Simplify right side
   1,379.09x = 1,560,575.22
5. Step 5: Solve for x
   x = 1,560,575.22/1,379.09
6. Step 6: Final answer
   x = 1,131.60