Finding the Fourth Proportional to 1,003.80, 1,502.46 and 678

Step by Step Solution

1. Step 1: Write the proportion equation
   1,003.80 : 1,502.46 = 678 : x
2. Step 2: Convert to fraction form
   1,003.80/1,502.46 = 678/x
3. Step 3: Cross multiply
   1,003.80x = 1,502.46 × 678
4. Step 4: Simplify right side
   1,003.80x = 1,018,667.88
5. Step 5: Solve for x
   x = 1,018,667.88/1,003.80
6. Step 6: Final answer
   x = 1,014.81