Finding the Fourth Proportional to 1,641.78, 2,266.20 and 978.84

Step by Step Solution

1. Step 1: Write the proportion equation
   1,641.78 : 2,266.20 = 978.84 : x
2. Step 2: Convert to fraction form
   1,641.78/2,266.20 = 978.84/x
3. Step 3: Cross multiply
   1,641.78x = 2,266.20 × 978.84
4. Step 4: Simplify right side
   1,641.78x = 2,218,247.21
5. Step 5: Solve for x
   x = 2,218,247.21/1,641.78
6. Step 6: Final answer
   x = 1,351.12