Finding the Fourth Proportional to 67.89, 100.69 and 67.20

Step by Step Solution

1. Step 1: Write the proportion equation
   67.89 : 100.69 = 67.20 : x
2. Step 2: Convert to fraction form
   67.89/100.69 = 67.20/x
3. Step 3: Cross multiply
   67.89x = 100.69 × 67.20
4. Step 4: Simplify right side
   67.89x = 6,767.05
5. Step 5: Solve for x
   x = 6,767.05/67.89
6. Step 6: Final answer
   x = 99.68