Finding the Fourth Proportional to 99.79, 137.72 and 67.12

Step by Step Solution

1. Step 1: Write the proportion equation
   99.79 : 137.72 = 67.12 : x
2. Step 2: Convert to fraction form
   99.79/137.72 = 67.12/x
3. Step 3: Cross multiply
   99.79x = 137.72 × 67.12
4. Step 4: Simplify right side
   99.79x = 9,243.77
5. Step 5: Solve for x
   x = 9,243.77/99.79
6. Step 6: Final answer
   x = 92.63