Finding the Fourth Proportional to 1,231.50, 1,699.59 and 679.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,231.50 : 1,699.59 = 679.50 : x
2. Step 2: Convert to fraction form
   1,231.50/1,699.59 = 679.50/x
3. Step 3: Cross multiply
   1,231.50x = 1,699.59 × 679.50
4. Step 4: Simplify right side
   1,231.50x = 1,154,871.41
5. Step 5: Solve for x
   x = 1,154,871.41/1,231.50
6. Step 6: Final answer
   x = 937.78