Finding the Fourth Proportional to 1,379.78, 1,904.34 and 820.44

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.78 : 1,904.34 = 820.44 : x
2. Step 2: Convert to fraction form
   1,379.78/1,904.34 = 820.44/x
3. Step 3: Cross multiply
   1,379.78x = 1,904.34 × 820.44
4. Step 4: Simplify right side
   1,379.78x = 1,562,396.71
5. Step 5: Solve for x
   x = 1,562,396.71/1,379.78
6. Step 6: Final answer
   x = 1,132.36