Finding the Fourth Proportional to 105,139.68, 145,144.80 and 64,875.63

Step by Step Solution

1. Step 1: Write the proportion equation
   105,139.68 : 145,144.80 = 64,875.63 : x
2. Step 2: Convert to fraction form
   105,139.68/145,144.80 = 64,875.63/x
3. Step 3: Cross multiply
   105,139.68x = 145,144.80 × 64,875.63
4. Step 4: Simplify right side
   105,139.68x = 9,416,360,341.22
5. Step 5: Solve for x
   x = 9,416,360,341.22/105,139.68
6. Step 6: Final answer
   x = 89,560.48