Finding the Fourth Proportional to 1,087.80, 1,501.08 and 668.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,087.80 : 1,501.08 = 668.15 : x
2. Step 2: Convert to fraction form
   1,087.80/1,501.08 = 668.15/x
3. Step 3: Cross multiply
   1,087.80x = 1,501.08 × 668.15
4. Step 4: Simplify right side
   1,087.80x = 1,002,939.10
5. Step 5: Solve for x
   x = 1,002,939.10/1,087.80
6. Step 6: Final answer
   x = 921.99