Finding the Fourth Proportional to 1,208.15, 1,667.28 and 788.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,208.15 : 1,667.28 = 788.77 : x
2. Step 2: Convert to fraction form
   1,208.15/1,667.28 = 788.77/x
3. Step 3: Cross multiply
   1,208.15x = 1,667.28 × 788.77
4. Step 4: Simplify right side
   1,208.15x = 1,315,105.49
5. Step 5: Solve for x
   x = 1,315,105.49/1,208.15
6. Step 6: Final answer
   x = 1,088.53