Finding the Fourth Proportional to 1,380.67, 1,905.59 and 791.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.67 : 1,905.59 = 791.60 : x
2. Step 2: Convert to fraction form
   1,380.67/1,905.59 = 791.60/x
3. Step 3: Cross multiply
   1,380.67x = 1,905.59 × 791.60
4. Step 4: Simplify right side
   1,380.67x = 1,508,457.50
5. Step 5: Solve for x
   x = 1,508,457.50/1,380.67
6. Step 6: Final answer
   x = 1,092.56