Finding the Fourth Proportional to 42,665.75, 64,010.90 and 13,087.92

Step by Step Solution

1. Step 1: Write the proportion equation
   42,665.75 : 64,010.90 = 13,087.92 : x
2. Step 2: Convert to fraction form
   42,665.75/64,010.90 = 13,087.92/x
3. Step 3: Cross multiply
   42,665.75x = 64,010.90 × 13,087.92
4. Step 4: Simplify right side
   42,665.75x = 837,769,571.05
5. Step 5: Solve for x
   x = 837,769,571.05/42,665.75
6. Step 6: Final answer
   x = 19,635.65