Finding the Fourth Proportional to 2,078.34, 3,117.90 and 691.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,078.34 : 3,117.90 = 691.76 : x
2. Step 2: Convert to fraction form
   2,078.34/3,117.90 = 691.76/x
3. Step 3: Cross multiply
   2,078.34x = 3,117.90 × 691.76
4. Step 4: Simplify right side
   2,078.34x = 2,156,822.91
5. Step 5: Solve for x
   x = 2,156,822.91/2,078.34
6. Step 6: Final answer
   x = 1,037.76