Finding the Fourth Proportional to 9,987.42, 13,782.81 and 5,511.20

Step by Step Solution

1. Step 1: Write the proportion equation
   9,987.42 : 13,782.81 = 5,511.20 : x
2. Step 2: Convert to fraction form
   9,987.42/13,782.81 = 5,511.20/x
3. Step 3: Cross multiply
   9,987.42x = 13,782.81 × 5,511.20
4. Step 4: Simplify right side
   9,987.42x = 75,959,753.56
5. Step 5: Solve for x
   x = 75,959,753.56/9,987.42
6. Step 6: Final answer
   x = 7,605.54