Finding the Fourth Proportional to 123,428.45, 170,322.35 and 72,443.21

Step by Step Solution

1. Step 1: Write the proportion equation
   123,428.45 : 170,322.35 = 72,443.21 : x
2. Step 2: Convert to fraction form
   123,428.45/170,322.35 = 72,443.21/x
3. Step 3: Cross multiply
   123,428.45x = 170,322.35 × 72,443.21
4. Step 4: Simplify right side
   123,428.45x = 12,338,696,554.92
5. Step 5: Solve for x
   x = 12,338,696,554.92/123,428.45
6. Step 6: Final answer
   x = 99,966.39