Finding the Fourth Proportional to 78.90, 108.72 and 69.59

Step by Step Solution

1. Step 1: Write the proportion equation
   78.90 : 108.72 = 69.59 : x
2. Step 2: Convert to fraction form
   78.90/108.72 = 69.59/x
3. Step 3: Cross multiply
   78.90x = 108.72 × 69.59
4. Step 4: Simplify right side
   78.90x = 7,565.28
5. Step 5: Solve for x
   x = 7,565.28/78.90
6. Step 6: Final answer
   x = 95.88