Finding the Fourth Proportional to 1,386.45, 1,909.17 and 992.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,386.45 : 1,909.17 = 992.79 : x
2. Step 2: Convert to fraction form
   1,386.45/1,909.17 = 992.79/x
3. Step 3: Cross multiply
   1,386.45x = 1,909.17 × 992.79
4. Step 4: Simplify right side
   1,386.45x = 1,895,404.88
5. Step 5: Solve for x
   x = 1,895,404.88/1,386.45
6. Step 6: Final answer
   x = 1,367.09