Finding the Fourth Proportional to 9,786.21, 13,504.87 and 5,479.31

Step by Step Solution

1. Step 1: Write the proportion equation
   9,786.21 : 13,504.87 = 5,479.31 : x
2. Step 2: Convert to fraction form
   9,786.21/13,504.87 = 5,479.31/x
3. Step 3: Cross multiply
   9,786.21x = 13,504.87 × 5,479.31
4. Step 4: Simplify right side
   9,786.21x = 73,997,409.85
5. Step 5: Solve for x
   x = 73,997,409.85/9,786.21
6. Step 6: Final answer
   x = 7,561.40