Finding the Fourth Proportional to 1,390.67, 1,918.69 and 892.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.67 : 1,918.69 = 892.42 : x
2. Step 2: Convert to fraction form
   1,390.67/1,918.69 = 892.42/x
3. Step 3: Cross multiply
   1,390.67x = 1,918.69 × 892.42
4. Step 4: Simplify right side
   1,390.67x = 1,712,270.30
5. Step 5: Solve for x
   x = 1,712,270.30/1,390.67
6. Step 6: Final answer
   x = 1,231.26