Finding the Fourth Proportional to 1,139.52, 1,572.84 and 667.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.52 : 1,572.84 = 667.56 : x
2. Step 2: Convert to fraction form
   1,139.52/1,572.84 = 667.56/x
3. Step 3: Cross multiply
   1,139.52x = 1,572.84 × 667.56
4. Step 4: Simplify right side
   1,139.52x = 1,049,965.07
5. Step 5: Solve for x
   x = 1,049,965.07/1,139.52
6. Step 6: Final answer
   x = 921.41