Finding the Fourth Proportional to 1,307.72, 1,959.36 and 648.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,307.72 : 1,959.36 = 648.72 : x
2. Step 2: Convert to fraction form
   1,307.72/1,959.36 = 648.72/x
3. Step 3: Cross multiply
   1,307.72x = 1,959.36 × 648.72
4. Step 4: Simplify right side
   1,307.72x = 1,271,076.02
5. Step 5: Solve for x
   x = 1,271,076.02/1,307.72
6. Step 6: Final answer
   x = 971.98