Finding the Fourth Proportional to 1,641.15, 2,264.85 and 978.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,641.15 : 2,264.85 = 978.15 : x
2. Step 2: Convert to fraction form
   1,641.15/2,264.85 = 978.15/x
3. Step 3: Cross multiply
   1,641.15x = 2,264.85 × 978.15
4. Step 4: Simplify right side
   1,641.15x = 2,215,363.03
5. Step 5: Solve for x
   x = 2,215,363.03/1,641.15
6. Step 6: Final answer
   x = 1,349.88