Finding the Fourth Proportional to 1,408.94, 2,113.72 and 678.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,408.94 : 2,113.72 = 678.12 : x
2. Step 2: Convert to fraction form
   1,408.94/2,113.72 = 678.12/x
3. Step 3: Cross multiply
   1,408.94x = 2,113.72 × 678.12
4. Step 4: Simplify right side
   1,408.94x = 1,433,355.81
5. Step 5: Solve for x
   x = 1,433,355.81/1,408.94
6. Step 6: Final answer
   x = 1,017.33