Finding the Fourth Proportional to 70.25, 105.15 and 42.75

Step by Step Solution

1. Step 1: Write the proportion equation
   70.25 : 105.15 = 42.75 : x
2. Step 2: Convert to fraction form
   70.25/105.15 = 42.75/x
3. Step 3: Cross multiply
   70.25x = 105.15 × 42.75
4. Step 4: Simplify right side
   70.25x = 4,495.32
5. Step 5: Solve for x
   x = 4,495.32/70.25
6. Step 6: Final answer
   x = 63.99