Finding the Fourth Proportional to 1,380.67, 1,904.77 and 790.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.67 : 1,904.77 = 790.89 : x
2. Step 2: Convert to fraction form
   1,380.67/1,904.77 = 790.89/x
3. Step 3: Cross multiply
   1,380.67x = 1,904.77 × 790.89
4. Step 4: Simplify right side
   1,380.67x = 1,506,463.55
5. Step 5: Solve for x
   x = 1,506,463.55/1,380.67
6. Step 6: Final answer
   x = 1,091.11