Finding the Fourth Proportional to 42,742.20, 64,120.32 and 13,160.04

Step by Step Solution

1. Step 1: Write the proportion equation
   42,742.20 : 64,120.32 = 13,160.04 : x
2. Step 2: Convert to fraction form
   42,742.20/64,120.32 = 13,160.04/x
3. Step 3: Cross multiply
   42,742.20x = 64,120.32 × 13,160.04
4. Step 4: Simplify right side
   42,742.20x = 843,825,976.01
5. Step 5: Solve for x
   x = 843,825,976.01/42,742.20
6. Step 6: Final answer
   x = 19,742.22