Finding the Fourth Proportional to 1,018.81, 1,405.12 and 721.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,018.81 : 1,405.12 = 721.06 : x
2. Step 2: Convert to fraction form
   1,018.81/1,405.12 = 721.06/x
3. Step 3: Cross multiply
   1,018.81x = 1,405.12 × 721.06
4. Step 4: Simplify right side
   1,018.81x = 1,013,175.83
5. Step 5: Solve for x
   x = 1,013,175.83/1,018.81
6. Step 6: Final answer
   x = 994.47