Finding the Fourth Proportional to 1,568.28, 2,164.24 and 978.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,568.28 : 2,164.24 = 978.78 : x
2. Step 2: Convert to fraction form
   1,568.28/2,164.24 = 978.78/x
3. Step 3: Cross multiply
   1,568.28x = 2,164.24 × 978.78
4. Step 4: Simplify right side
   1,568.28x = 2,118,314.83
5. Step 5: Solve for x
   x = 2,118,314.83/1,568.28
6. Step 6: Final answer
   x = 1,350.72