Finding the Fourth Proportional to 1,439.91, 2,155.50 and 788.67

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.91 : 2,155.50 = 788.67 : x
2. Step 2: Convert to fraction form
   1,439.91/2,155.50 = 788.67/x
3. Step 3: Cross multiply
   1,439.91x = 2,155.50 × 788.67
4. Step 4: Simplify right side
   1,439.91x = 1,699,978.19
5. Step 5: Solve for x
   x = 1,699,978.19/1,439.91
6. Step 6: Final answer
   x = 1,180.61