Finding the Fourth Proportional to 1,243.86, 1,715.82 and 777.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,243.86 : 1,715.82 = 777.30 : x
2. Step 2: Convert to fraction form
   1,243.86/1,715.82 = 777.30/x
3. Step 3: Cross multiply
   1,243.86x = 1,715.82 × 777.30
4. Step 4: Simplify right side
   1,243.86x = 1,333,715.29
5. Step 5: Solve for x
   x = 1,333,715.29/1,243.86
6. Step 6: Final answer
   x = 1,072.24