Finding the Fourth Proportional to 1,109.72, 1,664.60 and 379.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,109.72 : 1,664.60 = 379.30 : x
2. Step 2: Convert to fraction form
   1,109.72/1,664.60 = 379.30/x
3. Step 3: Cross multiply
   1,109.72x = 1,664.60 × 379.30
4. Step 4: Simplify right side
   1,109.72x = 631,382.78
5. Step 5: Solve for x
   x = 631,382.78/1,109.72
6. Step 6: Final answer
   x = 568.96