Finding the Fourth Proportional to 105,429.21, 145,515.65 and 72,769.47

Step by Step Solution

1. Step 1: Write the proportion equation
   105,429.21 : 145,515.65 = 72,769.47 : x
2. Step 2: Convert to fraction form
   105,429.21/145,515.65 = 72,769.47/x
3. Step 3: Cross multiply
   105,429.21x = 145,515.65 × 72,769.47
4. Step 4: Simplify right side
   105,429.21x = 10,589,096,727.21
5. Step 5: Solve for x
   x = 10,589,096,727.21/105,429.21
6. Step 6: Final answer
   x = 100,437.98