Finding the Fourth Proportional to 42,819.28, 64,229.40 and 19,128.04

Step by Step Solution

1. Step 1: Write the proportion equation
   42,819.28 : 64,229.40 = 19,128.04 : x
2. Step 2: Convert to fraction form
   42,819.28/64,229.40 = 19,128.04/x
3. Step 3: Cross multiply
   42,819.28x = 64,229.40 × 19,128.04
4. Step 4: Simplify right side
   42,819.28x = 1,228,582,532.38
5. Step 5: Solve for x
   x = 1,228,582,532.38/42,819.28
6. Step 6: Final answer
   x = 28,692.27