Finding the Fourth Proportional to 1,215.73, 1,677.72 and 691.66

Step by Step Solution

1. Step 1: Write the proportion equation
   1,215.73 : 1,677.72 = 691.66 : x
2. Step 2: Convert to fraction form
   1,215.73/1,677.72 = 691.66/x
3. Step 3: Cross multiply
   1,215.73x = 1,677.72 × 691.66
4. Step 4: Simplify right side
   1,215.73x = 1,160,411.82
5. Step 5: Solve for x
   x = 1,160,411.82/1,215.73
6. Step 6: Final answer
   x = 954.50