Finding the Fourth Proportional to 1,379.80, 1,904.17 and 790.53

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.80 : 1,904.17 = 790.53 : x
2. Step 2: Convert to fraction form
   1,379.80/1,904.17 = 790.53/x
3. Step 3: Cross multiply
   1,379.80x = 1,904.17 × 790.53
4. Step 4: Simplify right side
   1,379.80x = 1,505,303.51
5. Step 5: Solve for x
   x = 1,505,303.51/1,379.80
6. Step 6: Final answer
   x = 1,090.96