Finding the Fourth Proportional to 72,080.78, 99,518.28 and 64,513.99

Step by Step Solution

1. Step 1: Write the proportion equation
   72,080.78 : 99,518.28 = 64,513.99 : x
2. Step 2: Convert to fraction form
   72,080.78/99,518.28 = 64,513.99/x
3. Step 3: Cross multiply
   72,080.78x = 99,518.28 × 64,513.99
4. Step 4: Simplify right side
   72,080.78x = 6,420,321,687.06
5. Step 5: Solve for x
   x = 6,420,321,687.06/72,080.78
6. Step 6: Final answer
   x = 89,071.20