Finding the Fourth Proportional to 111.21, 166.50 and 64.80

Step by Step Solution

1. Step 1: Write the proportion equation
   111.21 : 166.50 = 64.80 : x
2. Step 2: Convert to fraction form
   111.21/166.50 = 64.80/x
3. Step 3: Cross multiply
   111.21x = 166.50 × 64.80
4. Step 4: Simplify right side
   111.21x = 10,788.55
5. Step 5: Solve for x
   x = 10,788.55/111.21
6. Step 6: Final answer
   x = 97.01