Finding the Fourth Proportional to 1,394.72, 1,923.72 and 870.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,394.72 : 1,923.72 = 870.56 : x
2. Step 2: Convert to fraction form
   1,394.72/1,923.72 = 870.56/x
3. Step 3: Cross multiply
   1,394.72x = 1,923.72 × 870.56
4. Step 4: Simplify right side
   1,394.72x = 1,674,713.68
5. Step 5: Solve for x
   x = 1,674,713.68/1,394.72
6. Step 6: Final answer
   x = 1,200.75