Finding the Fourth Proportional to 71,639.72, 107,431.50 and 42,065

Step by Step Solution

1. Step 1: Write the proportion equation
   71,639.72 : 107,431.50 = 42,065 : x
2. Step 2: Convert to fraction form
   71,639.72/107,431.50 = 42,065/x
3. Step 3: Cross multiply
   71,639.72x = 107,431.50 × 42,065
4. Step 4: Simplify right side
   71,639.72x = 4,519,106,047.50
5. Step 5: Solve for x
   x = 4,519,106,047.50/71,639.72
6. Step 6: Final answer
   x = 63,081.01