Finding the Fourth Proportional to 1,394.40, 1,924.80 and 870.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,394.40 : 1,924.80 = 870.56 : x
2. Step 2: Convert to fraction form
   1,394.40/1,924.80 = 870.56/x
3. Step 3: Cross multiply
   1,394.40x = 1,924.80 × 870.56
4. Step 4: Simplify right side
   1,394.40x = 1,675,653.89
5. Step 5: Solve for x
   x = 1,675,653.89/1,394.40
6. Step 6: Final answer
   x = 1,201.70