Finding the Fourth Proportional to 81,720, 112,698.72 and 53,009.76

Step by Step Solution

1. Step 1: Write the proportion equation
   81,720 : 112,698.72 = 53,009.76 : x
2. Step 2: Convert to fraction form
   81,720/112,698.72 = 53,009.76/x
3. Step 3: Cross multiply
   81,720x = 112,698.72 × 53,009.76
4. Step 4: Simplify right side
   81,720x = 5,974,132,099.51
5. Step 5: Solve for x
   x = 5,974,132,099.51/81,720
6. Step 6: Final answer
   x = 73,104.90