Finding the Fourth Proportional to 9,987.81, 13,783.31 and 5,511.75

Step by Step Solution

1. Step 1: Write the proportion equation
   9,987.81 : 13,783.31 = 5,511.75 : x
2. Step 2: Convert to fraction form
   9,987.81/13,783.31 = 5,511.75/x
3. Step 3: Cross multiply
   9,987.81x = 13,783.31 × 5,511.75
4. Step 4: Simplify right side
   9,987.81x = 75,970,131.32
5. Step 5: Solve for x
   x = 75,970,131.32/9,987.81
6. Step 6: Final answer
   x = 7,606.29