Finding the Fourth Proportional to 83,315.20, 115,196.16 and 72,817.60

Step by Step Solution

1. Step 1: Write the proportion equation
   83,315.20 : 115,196.16 = 72,817.60 : x
2. Step 2: Convert to fraction form
   83,315.20/115,196.16 = 72,817.60/x
3. Step 3: Cross multiply
   83,315.20x = 115,196.16 × 72,817.60
4. Step 4: Simplify right side
   83,315.20x = 8,388,307,900.42
5. Step 5: Solve for x
   x = 8,388,307,900.42/83,315.20
6. Step 6: Final answer
   x = 100,681.60