Finding the Fourth Proportional to 78.58, 108.69 and 70.39

Step by Step Solution

1. Step 1: Write the proportion equation
   78.58 : 108.69 = 70.39 : x
2. Step 2: Convert to fraction form
   78.58/108.69 = 70.39/x
3. Step 3: Cross multiply
   78.58x = 108.69 × 70.39
4. Step 4: Simplify right side
   78.58x = 7,650.69
5. Step 5: Solve for x
   x = 7,650.69/78.58
6. Step 6: Final answer
   x = 97.36