Finding the Fourth Proportional to 1,345.83, 2,017.80 and 687.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,345.83 : 2,017.80 = 687.91 : x
2. Step 2: Convert to fraction form
   1,345.83/2,017.80 = 687.91/x
3. Step 3: Cross multiply
   1,345.83x = 2,017.80 × 687.91
4. Step 4: Simplify right side
   1,345.83x = 1,388,064.80
5. Step 5: Solve for x
   x = 1,388,064.80/1,345.83
6. Step 6: Final answer
   x = 1,031.38