Finding the Fourth Proportional to 105,271.68, 145,315.20 and 64,992

Step by Step Solution

1. Step 1: Write the proportion equation
   105,271.68 : 145,315.20 = 64,992 : x
2. Step 2: Convert to fraction form
   105,271.68/145,315.20 = 64,992/x
3. Step 3: Cross multiply
   105,271.68x = 145,315.20 × 64,992
4. Step 4: Simplify right side
   105,271.68x = 9,444,325,478.40
5. Step 5: Solve for x
   x = 9,444,325,478.40/105,271.68
6. Step 6: Final answer
   x = 89,713.83