Finding the Fourth Proportional to 2,075.31, 3,111.95 and 688.18

Step by Step Solution

1. Step 1: Write the proportion equation
   2,075.31 : 3,111.95 = 688.18 : x
2. Step 2: Convert to fraction form
   2,075.31/3,111.95 = 688.18/x
3. Step 3: Cross multiply
   2,075.31x = 3,111.95 × 688.18
4. Step 4: Simplify right side
   2,075.31x = 2,141,581.75
5. Step 5: Solve for x
   x = 2,141,581.75/2,075.31
6. Step 6: Final answer
   x = 1,031.93