Finding the Fourth Proportional to 128.76, 193.15 and 42.10

Step by Step Solution

1. Step 1: Write the proportion equation
   128.76 : 193.15 = 42.10 : x
2. Step 2: Convert to fraction form
   128.76/193.15 = 42.10/x
3. Step 3: Cross multiply
   128.76x = 193.15 × 42.10
4. Step 4: Simplify right side
   128.76x = 8,132.29
5. Step 5: Solve for x
   x = 8,132.29/128.76
6. Step 6: Final answer
   x = 63.16