Finding the Fourth Proportional to 1,139.42, 1,572.48 and 667.19

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.42 : 1,572.48 = 667.19 : x
2. Step 2: Convert to fraction form
   1,139.42/1,572.48 = 667.19/x
3. Step 3: Cross multiply
   1,139.42x = 1,572.48 × 667.19
4. Step 4: Simplify right side
   1,139.42x = 1,049,146.86
5. Step 5: Solve for x
   x = 1,049,146.86/1,139.42
6. Step 6: Final answer
   x = 920.77