Finding the Fourth Proportional to 1,408.21, 1,943.37 and 778.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,408.21 : 1,943.37 = 778.78 : x
2. Step 2: Convert to fraction form
   1,408.21/1,943.37 = 778.78/x
3. Step 3: Cross multiply
   1,408.21x = 1,943.37 × 778.78
4. Step 4: Simplify right side
   1,408.21x = 1,513,457.69
5. Step 5: Solve for x
   x = 1,513,457.69/1,408.21
6. Step 6: Final answer
   x = 1,074.74