Finding the Fourth Proportional to 1,109.78, 1,664.86 and 329.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,109.78 : 1,664.86 = 329.76 : x
2. Step 2: Convert to fraction form
   1,109.78/1,664.86 = 329.76/x
3. Step 3: Cross multiply
   1,109.78x = 1,664.86 × 329.76
4. Step 4: Simplify right side
   1,109.78x = 549,004.23
5. Step 5: Solve for x
   x = 549,004.23/1,109.78
6. Step 6: Final answer
   x = 494.70