Finding the Fourth Proportional to 139.16, 208.72 and 42.98

Step by Step Solution

1. Step 1: Write the proportion equation
   139.16 : 208.72 = 42.98 : x
2. Step 2: Convert to fraction form
   139.16/208.72 = 42.98/x
3. Step 3: Cross multiply
   139.16x = 208.72 × 42.98
4. Step 4: Simplify right side
   139.16x = 8,970.79
5. Step 5: Solve for x
   x = 8,970.79/139.16
6. Step 6: Final answer
   x = 64.46