Finding the Fourth Proportional to 65,324.78, 89,561.30 and 64,143.80

Step by Step Solution

1. Step 1: Write the proportion equation
   65,324.78 : 89,561.30 = 64,143.80 : x
2. Step 2: Convert to fraction form
   65,324.78/89,561.30 = 64,143.80/x
3. Step 3: Cross multiply
   65,324.78x = 89,561.30 × 64,143.80
4. Step 4: Simplify right side
   65,324.78x = 5,744,801,682.27
5. Step 5: Solve for x
   x = 5,744,801,682.27/65,324.78
6. Step 6: Final answer
   x = 87,942.15