Finding the Fourth Proportional to 1,366.69, 1,885.90 and 777.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,366.69 : 1,885.90 = 777.20 : x
2. Step 2: Convert to fraction form
   1,366.69/1,885.90 = 777.20/x
3. Step 3: Cross multiply
   1,366.69x = 1,885.90 × 777.20
4. Step 4: Simplify right side
   1,366.69x = 1,465,719.54
5. Step 5: Solve for x
   x = 1,465,719.54/1,366.69
6. Step 6: Final answer
   x = 1,072.46