Finding the Fourth Proportional to 28,617.42, 42,936.45 and 12,821.10

Step by Step Solution

1. Step 1: Write the proportion equation
   28,617.42 : 42,936.45 = 12,821.10 : x
2. Step 2: Convert to fraction form
   28,617.42/42,936.45 = 12,821.10/x
3. Step 3: Cross multiply
   28,617.42x = 42,936.45 × 12,821.10
4. Step 4: Simplify right side
   28,617.42x = 550,492,519.10
5. Step 5: Solve for x
   x = 550,492,519.10/28,617.42
6. Step 6: Final answer
   x = 19,236.27