Finding the Fourth Proportional to 1,109.98, 1,665.60 and 379.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,109.98 : 1,665.60 = 379.72 : x
2. Step 2: Convert to fraction form
   1,109.98/1,665.60 = 379.72/x
3. Step 3: Cross multiply
   1,109.98x = 1,665.60 × 379.72
4. Step 4: Simplify right side
   1,109.98x = 632,461.63
5. Step 5: Solve for x
   x = 632,461.63/1,109.98
6. Step 6: Final answer
   x = 569.80