Finding the Fourth Proportional to 1,438.86, 2,158.56 and 573.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,438.86 : 2,158.56 = 573.78 : x
2. Step 2: Convert to fraction form
   1,438.86/2,158.56 = 573.78/x
3. Step 3: Cross multiply
   1,438.86x = 2,158.56 × 573.78
4. Step 4: Simplify right side
   1,438.86x = 1,238,538.56
5. Step 5: Solve for x
   x = 1,238,538.56/1,438.86
6. Step 6: Final answer
   x = 860.78