Finding the Fourth Proportional to 1,379.90, 1,904.10 and 790.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.90 : 1,904.10 = 790.55 : x
2. Step 2: Convert to fraction form
   1,379.90/1,904.10 = 790.55/x
3. Step 3: Cross multiply
   1,379.90x = 1,904.10 × 790.55
4. Step 4: Simplify right side
   1,379.90x = 1,505,276.73
5. Step 5: Solve for x
   x = 1,505,276.73/1,379.90
6. Step 6: Final answer
   x = 1,090.86