Finding the Fourth Proportional to 1,109.15, 1,530.02 and 666.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,109.15 : 1,530.02 = 666.78 : x
2. Step 2: Convert to fraction form
   1,109.15/1,530.02 = 666.78/x
3. Step 3: Cross multiply
   1,109.15x = 1,530.02 × 666.78
4. Step 4: Simplify right side
   1,109.15x = 1,020,183.40
5. Step 5: Solve for x
   x = 1,020,183.40/1,109.15
6. Step 6: Final answer
   x = 919.79