Finding the Fourth Proportional to 105.31, 157.98 and 64.21

Step by Step Solution

1. Step 1: Write the proportion equation
   105.31 : 157.98 = 64.21 : x
2. Step 2: Convert to fraction form
   105.31/157.98 = 64.21/x
3. Step 3: Cross multiply
   105.31x = 157.98 × 64.21
4. Step 4: Simplify right side
   105.31x = 10,143.90
5. Step 5: Solve for x
   x = 10,143.90/105.31
6. Step 6: Final answer
   x = 96.32