Finding the Fourth Proportional to 28,238.42, 42,364.47 and 8,515.78

Step by Step Solution

1. Step 1: Write the proportion equation
   28,238.42 : 42,364.47 = 8,515.78 : x
2. Step 2: Convert to fraction form
   28,238.42/42,364.47 = 8,515.78/x
3. Step 3: Cross multiply
   28,238.42x = 42,364.47 × 8,515.78
4. Step 4: Simplify right side
   28,238.42x = 360,766,622.76
5. Step 5: Solve for x
   x = 360,766,622.76/28,238.42
6. Step 6: Final answer
   x = 12,775.74