Finding the Fourth Proportional to 1,138.89, 1,571.74 and 667.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,138.89 : 1,571.74 = 667.10 : x
2. Step 2: Convert to fraction form
   1,138.89/1,571.74 = 667.10/x
3. Step 3: Cross multiply
   1,138.89x = 1,571.74 × 667.10
4. Step 4: Simplify right side
   1,138.89x = 1,048,510.02
5. Step 5: Solve for x
   x = 1,048,510.02/1,138.89
6. Step 6: Final answer
   x = 920.64