Finding the Fourth Proportional to 1,258.72, 1,886.76 and 478.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,258.72 : 1,886.76 = 478.60 : x
2. Step 2: Convert to fraction form
   1,258.72/1,886.76 = 478.60/x
3. Step 3: Cross multiply
   1,258.72x = 1,886.76 × 478.60
4. Step 4: Simplify right side
   1,258.72x = 903,003.34
5. Step 5: Solve for x
   x = 903,003.34/1,258.72
6. Step 6: Final answer
   x = 717.40