Finding the Fourth Proportional to 76,689.80, 105,920.56 and 51,151.82

Step by Step Solution

1. Step 1: Write the proportion equation
   76,689.80 : 105,920.56 = 51,151.82 : x
2. Step 2: Convert to fraction form
   76,689.80/105,920.56 = 51,151.82/x
3. Step 3: Cross multiply
   76,689.80x = 105,920.56 × 51,151.82
4. Step 4: Simplify right side
   76,689.80x = 5,418,029,419.42
5. Step 5: Solve for x
   x = 5,418,029,419.42/76,689.80
6. Step 6: Final answer
   x = 70,648.63