Finding the Fourth Proportional to 91.54, 137.34 and 42.80

Step by Step Solution

1. Step 1: Write the proportion equation
   91.54 : 137.34 = 42.80 : x
2. Step 2: Convert to fraction form
   91.54/137.34 = 42.80/x
3. Step 3: Cross multiply
   91.54x = 137.34 × 42.80
4. Step 4: Simplify right side
   91.54x = 5,878.15
5. Step 5: Solve for x
   x = 5,878.15/91.54
6. Step 6: Final answer
   x = 64.21