Finding the Fourth Proportional to 86,619.70, 129,820.20 and 42,150.70

Step by Step Solution

1. Step 1: Write the proportion equation
   86,619.70 : 129,820.20 = 42,150.70 : x
2. Step 2: Convert to fraction form
   86,619.70/129,820.20 = 42,150.70/x
3. Step 3: Cross multiply
   86,619.70x = 129,820.20 × 42,150.70
4. Step 4: Simplify right side
   86,619.70x = 5,472,012,304.14
5. Step 5: Solve for x
   x = 5,472,012,304.14/86,619.70
6. Step 6: Final answer
   x = 63,172.84