Finding the Fourth Proportional to 1,109.58, 1,531.08 and 668.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,109.58 : 1,531.08 = 668.10 : x
2. Step 2: Convert to fraction form
   1,109.58/1,531.08 = 668.10/x
3. Step 3: Cross multiply
   1,109.58x = 1,531.08 × 668.10
4. Step 4: Simplify right side
   1,109.58x = 1,022,914.55
5. Step 5: Solve for x
   x = 1,022,914.55/1,109.58
6. Step 6: Final answer
   x = 921.89