Finding the Fourth Proportional to 1,139.60, 1,572.35 and 667.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.60 : 1,572.35 = 667.24 : x
2. Step 2: Convert to fraction form
   1,139.60/1,572.35 = 667.24/x
3. Step 3: Cross multiply
   1,139.60x = 1,572.35 × 667.24
4. Step 4: Simplify right side
   1,139.60x = 1,049,127.55
5. Step 5: Solve for x
   x = 1,049,127.55/1,139.60
6. Step 6: Final answer
   x = 920.61