Finding the Fourth Proportional to 1,208.50, 1,667.70 and 711.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,208.50 : 1,667.70 = 711.15 : x
2. Step 2: Convert to fraction form
   1,208.50/1,667.70 = 711.15/x
3. Step 3: Cross multiply
   1,208.50x = 1,667.70 × 711.15
4. Step 4: Simplify right side
   1,208.50x = 1,185,984.86
5. Step 5: Solve for x
   x = 1,185,984.86/1,208.50
6. Step 6: Final answer
   x = 981.37