Finding the Fourth Proportional to 86,443, 129,680.20 and 42,069.78

Step by Step Solution

1. Step 1: Write the proportion equation
   86,443 : 129,680.20 = 42,069.78 : x
2. Step 2: Convert to fraction form
   86,443/129,680.20 = 42,069.78/x
3. Step 3: Cross multiply
   86,443x = 129,680.20 × 42,069.78
4. Step 4: Simplify right side
   86,443x = 5,455,617,484.36
5. Step 5: Solve for x
   x = 5,455,617,484.36/86,443
6. Step 6: Final answer
   x = 63,112.31