Finding the Fourth Proportional to 70.18, 105.30 and 42.79

Step by Step Solution

1. Step 1: Write the proportion equation
   70.18 : 105.30 = 42.79 : x
2. Step 2: Convert to fraction form
   70.18/105.30 = 42.79/x
3. Step 3: Cross multiply
   70.18x = 105.30 × 42.79
4. Step 4: Simplify right side
   70.18x = 4,505.52
5. Step 5: Solve for x
   x = 4,505.52/70.18
6. Step 6: Final answer
   x = 64.20