Finding the Fourth Proportional to 1,603.32, 2,405.40 and 678.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,603.32 : 2,405.40 = 678.91 : x
2. Step 2: Convert to fraction form
   1,603.32/2,405.40 = 678.91/x
3. Step 3: Cross multiply
   1,603.32x = 2,405.40 × 678.91
4. Step 4: Simplify right side
   1,603.32x = 1,633,046.72
5. Step 5: Solve for x
   x = 1,633,046.72/1,603.32
6. Step 6: Final answer
   x = 1,018.54