Finding the Fourth Proportional to 9,891.72, 13,644.52 and 7,764.05

Step by Step Solution

1. Step 1: Write the proportion equation
   9,891.72 : 13,644.52 = 7,764.05 : x
2. Step 2: Convert to fraction form
   9,891.72/13,644.52 = 7,764.05/x
3. Step 3: Cross multiply
   9,891.72x = 13,644.52 × 7,764.05
4. Step 4: Simplify right side
   9,891.72x = 105,936,750.21
5. Step 5: Solve for x
   x = 105,936,750.21/9,891.72
6. Step 6: Final answer
   x = 10,709.64