Finding the Fourth Proportional to 42,722.19, 64,090.56 and 13,139.37

Step by Step Solution

1. Step 1: Write the proportion equation
   42,722.19 : 64,090.56 = 13,139.37 : x
2. Step 2: Convert to fraction form
   42,722.19/64,090.56 = 13,139.37/x
3. Step 3: Cross multiply
   42,722.19x = 64,090.56 × 13,139.37
4. Step 4: Simplify right side
   42,722.19x = 842,109,581.35
5. Step 5: Solve for x
   x = 842,109,581.35/42,722.19
6. Step 6: Final answer
   x = 19,711.29