Finding the Fourth Proportional to 2,074.69, 3,111.63 and 687.70

Step by Step Solution

1. Step 1: Write the proportion equation
   2,074.69 : 3,111.63 = 687.70 : x
2. Step 2: Convert to fraction form
   2,074.69/3,111.63 = 687.70/x
3. Step 3: Cross multiply
   2,074.69x = 3,111.63 × 687.70
4. Step 4: Simplify right side
   2,074.69x = 2,139,867.95
5. Step 5: Solve for x
   x = 2,139,867.95/2,074.69
6. Step 6: Final answer
   x = 1,031.42