Finding the Fourth Proportional to 1,408.74, 2,113.59 and 678.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,408.74 : 2,113.59 = 678.38 : x
2. Step 2: Convert to fraction form
   1,408.74/2,113.59 = 678.38/x
3. Step 3: Cross multiply
   1,408.74x = 2,113.59 × 678.38
4. Step 4: Simplify right side
   1,408.74x = 1,433,809.16
5. Step 5: Solve for x
   x = 1,433,809.16/1,408.74
6. Step 6: Final answer
   x = 1,017.79