Finding the Fourth Proportional to 1,030.72, 1,544.64 and 688

Step by Step Solution

1. Step 1: Write the proportion equation
   1,030.72 : 1,544.64 = 688 : x
2. Step 2: Convert to fraction form
   1,030.72/1,544.64 = 688/x
3. Step 3: Cross multiply
   1,030.72x = 1,544.64 × 688
4. Step 4: Simplify right side
   1,030.72x = 1,062,712.32
5. Step 5: Solve for x
   x = 1,062,712.32/1,030.72
6. Step 6: Final answer
   x = 1,031.04