Finding the Fourth Proportional to 13,131.65, 18,118.46 and 8,422.31

Step by Step Solution

1. Step 1: Write the proportion equation
   13,131.65 : 18,118.46 = 8,422.31 : x
2. Step 2: Convert to fraction form
   13,131.65/18,118.46 = 8,422.31/x
3. Step 3: Cross multiply
   13,131.65x = 18,118.46 × 8,422.31
4. Step 4: Simplify right side
   13,131.65x = 152,599,154.14
5. Step 5: Solve for x
   x = 152,599,154.14/13,131.65
6. Step 6: Final answer
   x = 11,620.72