Finding the Fourth Proportional to 12,780.72, 17,636.04 and 7,190.64

Step by Step Solution

1. Step 1: Write the proportion equation
   12,780.72 : 17,636.04 = 7,190.64 : x
2. Step 2: Convert to fraction form
   12,780.72/17,636.04 = 7,190.64/x
3. Step 3: Cross multiply
   12,780.72x = 17,636.04 × 7,190.64
4. Step 4: Simplify right side
   12,780.72x = 126,814,414.67
5. Step 5: Solve for x
   x = 126,814,414.67/12,780.72
6. Step 6: Final answer
   x = 9,922.32