Finding the Fourth Proportional to 1,568.38, 2,164.71 and 978.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,568.38 : 2,164.71 = 978.80 : x
2. Step 2: Convert to fraction form
   1,568.38/2,164.71 = 978.80/x
3. Step 3: Cross multiply
   1,568.38x = 2,164.71 × 978.80
4. Step 4: Simplify right side
   1,568.38x = 2,118,818.15
5. Step 5: Solve for x
   x = 2,118,818.15/1,568.38
6. Step 6: Final answer
   x = 1,350.96