Finding the Fourth Proportional to 1,109.30, 1,663.74 and 415.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,109.30 : 1,663.74 = 415.89 : x
2. Step 2: Convert to fraction form
   1,109.30/1,663.74 = 415.89/x
3. Step 3: Cross multiply
   1,109.30x = 1,663.74 × 415.89
4. Step 4: Simplify right side
   1,109.30x = 691,932.83
5. Step 5: Solve for x
   x = 691,932.83/1,109.30
6. Step 6: Final answer
   x = 623.76