Finding the Fourth Proportional to 1,379.72, 1,903.58 and 790.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.72 : 1,903.58 = 790.15 : x
2. Step 2: Convert to fraction form
   1,379.72/1,903.58 = 790.15/x
3. Step 3: Cross multiply
   1,379.72x = 1,903.58 × 790.15
4. Step 4: Simplify right side
   1,379.72x = 1,504,104.22
5. Step 5: Solve for x
   x = 1,504,104.22/1,379.72
6. Step 6: Final answer
   x = 1,090.15