Finding the Fourth Proportional to 1,071.72, 1,478.64 and 629.64

Step by Step Solution

1. Step 1: Write the proportion equation
   1,071.72 : 1,478.64 = 629.64 : x
2. Step 2: Convert to fraction form
   1,071.72/1,478.64 = 629.64/x
3. Step 3: Cross multiply
   1,071.72x = 1,478.64 × 629.64
4. Step 4: Simplify right side
   1,071.72x = 931,010.89
5. Step 5: Solve for x
   x = 931,010.89/1,071.72
6. Step 6: Final answer
   x = 868.71