Finding the Fourth Proportional to 1,208.17, 1,667.28 and 710.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,208.17 : 1,667.28 = 710.78 : x
2. Step 2: Convert to fraction form
   1,208.17/1,667.28 = 710.78/x
3. Step 3: Cross multiply
   1,208.17x = 1,667.28 × 710.78
4. Step 4: Simplify right side
   1,208.17x = 1,185,063.61
5. Step 5: Solve for x
   x = 1,185,063.61/1,208.17
6. Step 6: Final answer
   x = 980.88