Finding the Fourth Proportional to 90.72, 136.12 and 79.98

Step by Step Solution

1. Step 1: Write the proportion equation
   90.72 : 136.12 = 79.98 : x
2. Step 2: Convert to fraction form
   90.72/136.12 = 79.98/x
3. Step 3: Cross multiply
   90.72x = 136.12 × 79.98
4. Step 4: Simplify right side
   90.72x = 10,886.88
5. Step 5: Solve for x
   x = 10,886.88/90.72
6. Step 6: Final answer
   x = 120.01