Finding the Fourth Proportional to 13,611.98, 20,405 and 4,371.50

Step by Step Solution

1. Step 1: Write the proportion equation
   13,611.98 : 20,405 = 4,371.50 : x
2. Step 2: Convert to fraction form
   13,611.98/20,405 = 4,371.50/x
3. Step 3: Cross multiply
   13,611.98x = 20,405 × 4,371.50
4. Step 4: Simplify right side
   13,611.98x = 89,200,457.50
5. Step 5: Solve for x
   x = 89,200,457.50/13,611.98
6. Step 6: Final answer
   x = 6,553.08