Finding the Fourth Proportional to 81,453.60, 112,499.28 and 64,890.72

Step by Step Solution

1. Step 1: Write the proportion equation
   81,453.60 : 112,499.28 = 64,890.72 : x
2. Step 2: Convert to fraction form
   81,453.60/112,499.28 = 64,890.72/x
3. Step 3: Cross multiply
   81,453.60x = 112,499.28 × 64,890.72
4. Step 4: Simplify right side
   81,453.60x = 7,300,159,278.68
5. Step 5: Solve for x
   x = 7,300,159,278.68/81,453.60
6. Step 6: Final answer
   x = 89,623.53