Finding the Fourth Proportional to 1,139.07, 1,571.87 and 667.01

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.07 : 1,571.87 = 667.01 : x
2. Step 2: Convert to fraction form
   1,139.07/1,571.87 = 667.01/x
3. Step 3: Cross multiply
   1,139.07x = 1,571.87 × 667.01
4. Step 4: Simplify right side
   1,139.07x = 1,048,441.81
5. Step 5: Solve for x
   x = 1,048,441.81/1,139.07
6. Step 6: Final answer
   x = 920.44