Finding the Fourth Proportional to 1,019.79, 1,408.12 and 665.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,019.79 : 1,408.12 = 665.96 : x
2. Step 2: Convert to fraction form
   1,019.79/1,408.12 = 665.96/x
3. Step 3: Cross multiply
   1,019.79x = 1,408.12 × 665.96
4. Step 4: Simplify right side
   1,019.79x = 937,742.89
5. Step 5: Solve for x
   x = 937,742.89/1,019.79
6. Step 6: Final answer
   x = 919.55