Finding the Fourth Proportional to 1,215.72, 1,677.53 and 691.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,215.72 : 1,677.53 = 691.76 : x
2. Step 2: Convert to fraction form
   1,215.72/1,677.53 = 691.76/x
3. Step 3: Cross multiply
   1,215.72x = 1,677.53 × 691.76
4. Step 4: Simplify right side
   1,215.72x = 1,160,448.15
5. Step 5: Solve for x
   x = 1,160,448.15/1,215.72
6. Step 6: Final answer
   x = 954.54