Finding the Fourth Proportional to 9,891.16, 13,649.82 and 5,415.20

Step by Step Solution

1. Step 1: Write the proportion equation
   9,891.16 : 13,649.82 = 5,415.20 : x
2. Step 2: Convert to fraction form
   9,891.16/13,649.82 = 5,415.20/x
3. Step 3: Cross multiply
   9,891.16x = 13,649.82 × 5,415.20
4. Step 4: Simplify right side
   9,891.16x = 73,916,505.26
5. Step 5: Solve for x
   x = 73,916,505.26/9,891.16
6. Step 6: Final answer
   x = 7,472.99