Finding the Fourth Proportional to 1,613.80, 2,419.17 and 688.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,613.80 : 2,419.17 = 688.78 : x
2. Step 2: Convert to fraction form
   1,613.80/2,419.17 = 688.78/x
3. Step 3: Cross multiply
   1,613.80x = 2,419.17 × 688.78
4. Step 4: Simplify right side
   1,613.80x = 1,666,275.91
5. Step 5: Solve for x
   x = 1,666,275.91/1,613.80
6. Step 6: Final answer
   x = 1,032.52