Finding the Fourth Proportional to 99.76, 149.56 and 42.80

Step by Step Solution

1. Step 1: Write the proportion equation
   99.76 : 149.56 = 42.80 : x
2. Step 2: Convert to fraction form
   99.76/149.56 = 42.80/x
3. Step 3: Cross multiply
   99.76x = 149.56 × 42.80
4. Step 4: Simplify right side
   99.76x = 6,401.17
5. Step 5: Solve for x
   x = 6,401.17/99.76
6. Step 6: Final answer
   x = 64.17