Finding the Fourth Proportional to 139.71, 209.50 and 74.69

Step by Step Solution

1. Step 1: Write the proportion equation
   139.71 : 209.50 = 74.69 : x
2. Step 2: Convert to fraction form
   139.71/209.50 = 74.69/x
3. Step 3: Cross multiply
   139.71x = 209.50 × 74.69
4. Step 4: Simplify right side
   139.71x = 15,647.94
5. Step 5: Solve for x
   x = 15,647.94/139.71
6. Step 6: Final answer
   x = 112.00