Finding the Fourth Proportional to 42,478.72, 63,718.38 and 12,896.91

Step by Step Solution

1. Step 1: Write the proportion equation
   42,478.72 : 63,718.38 = 12,896.91 : x
2. Step 2: Convert to fraction form
   42,478.72/63,718.38 = 12,896.91/x
3. Step 3: Cross multiply
   42,478.72x = 63,718.38 × 12,896.91
4. Step 4: Simplify right side
   42,478.72x = 821,770,212.21
5. Step 5: Solve for x
   x = 821,770,212.21/42,478.72
6. Step 6: Final answer
   x = 19,345.46