Finding the Fourth Proportional to 1,407.69, 1,942.63 and 778.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,407.69 : 1,942.63 = 778.21 : x
2. Step 2: Convert to fraction form
   1,407.69/1,942.63 = 778.21/x
3. Step 3: Cross multiply
   1,407.69x = 1,942.63 × 778.21
4. Step 4: Simplify right side
   1,407.69x = 1,511,767.29
5. Step 5: Solve for x
   x = 1,511,767.29/1,407.69
6. Step 6: Final answer
   x = 1,073.93