Finding the Fourth Proportional to 1,379.60, 1,903.72 and 790.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.60 : 1,903.72 = 790.12 : x
2. Step 2: Convert to fraction form
   1,379.60/1,903.72 = 790.12/x
3. Step 3: Cross multiply
   1,379.60x = 1,903.72 × 790.12
4. Step 4: Simplify right side
   1,379.60x = 1,504,167.25
5. Step 5: Solve for x
   x = 1,504,167.25/1,379.60
6. Step 6: Final answer
   x = 1,090.29