Finding the Fourth Proportional to 1,578.51, 2,178.30 and 870.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,578.51 : 2,178.30 = 870.38 : x
2. Step 2: Convert to fraction form
   1,578.51/2,178.30 = 870.38/x
3. Step 3: Cross multiply
   1,578.51x = 2,178.30 × 870.38
4. Step 4: Simplify right side
   1,578.51x = 1,895,937.86
5. Step 5: Solve for x
   x = 1,895,937.86/1,578.51
6. Step 6: Final answer
   x = 1,201.09