Finding the Fourth Proportional to 1,568.78, 2,164.82 and 870.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,568.78 : 2,164.82 = 870.15 : x
2. Step 2: Convert to fraction form
   1,568.78/2,164.82 = 870.15/x
3. Step 3: Cross multiply
   1,568.78x = 2,164.82 × 870.15
4. Step 4: Simplify right side
   1,568.78x = 1,883,713.77
5. Step 5: Solve for x
   x = 1,883,713.77/1,568.78
6. Step 6: Final answer
   x = 1,200.75