Finding the Fourth Proportional to 1,478.72, 2,213.79 and 860.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,478.72 : 2,213.79 = 860.54 : x
2. Step 2: Convert to fraction form
   1,478.72/2,213.79 = 860.54/x
3. Step 3: Cross multiply
   1,478.72x = 2,213.79 × 860.54
4. Step 4: Simplify right side
   1,478.72x = 1,905,054.85
5. Step 5: Solve for x
   x = 1,905,054.85/1,478.72
6. Step 6: Final answer
   x = 1,288.31