Finding the Fourth Proportional to 12,811.50, 17,680.68 and 7,222.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,811.50 : 17,680.68 = 7,222.50 : x
2. Step 2: Convert to fraction form
   12,811.50/17,680.68 = 7,222.50/x
3. Step 3: Cross multiply
   12,811.50x = 17,680.68 × 7,222.50
4. Step 4: Simplify right side
   12,811.50x = 127,698,711.30
5. Step 5: Solve for x
   x = 127,698,711.30/12,811.50
6. Step 6: Final answer
   x = 9,967.51