Finding the Fourth Proportional to 1,215.56, 1,677.62 and 691.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,215.56 : 1,677.62 = 691.72 : x
2. Step 2: Convert to fraction form
   1,215.56/1,677.62 = 691.72/x
3. Step 3: Cross multiply
   1,215.56x = 1,677.62 × 691.72
4. Step 4: Simplify right side
   1,215.56x = 1,160,443.31
5. Step 5: Solve for x
   x = 1,160,443.31/1,215.56
6. Step 6: Final answer
   x = 954.66