Finding the Fourth Proportional to 91.88, 126.72 and 72.17

Step by Step Solution

1. Step 1: Write the proportion equation
   91.88 : 126.72 = 72.17 : x
2. Step 2: Convert to fraction form
   91.88/126.72 = 72.17/x
3. Step 3: Cross multiply
   91.88x = 126.72 × 72.17
4. Step 4: Simplify right side
   91.88x = 9,145.38
5. Step 5: Solve for x
   x = 9,145.38/91.88
6. Step 6: Final answer
   x = 99.54