Finding the Fourth Proportional to 42,772.57, 64,155.78 and 13,187.32

Step by Step Solution

1. Step 1: Write the proportion equation
   42,772.57 : 64,155.78 = 13,187.32 : x
2. Step 2: Convert to fraction form
   42,772.57/64,155.78 = 13,187.32/x
3. Step 3: Cross multiply
   42,772.57x = 64,155.78 × 13,187.32
4. Step 4: Simplify right side
   42,772.57x = 846,042,800.71
5. Step 5: Solve for x
   x = 846,042,800.71/42,772.57
6. Step 6: Final answer
   x = 19,780.03