Finding the Fourth Proportional to 90,139.68, 135,170.06 and 42,768.28

Step by Step Solution

1. Step 1: Write the proportion equation
   90,139.68 : 135,170.06 = 42,768.28 : x
2. Step 2: Convert to fraction form
   90,139.68/135,170.06 = 42,768.28/x
3. Step 3: Cross multiply
   90,139.68x = 135,170.06 × 42,768.28
4. Step 4: Simplify right side
   90,139.68x = 5,780,990,084.01
5. Step 5: Solve for x
   x = 5,780,990,084.01/90,139.68
6. Step 6: Final answer
   x = 64,133.69