Finding the Fourth Proportional to 105.72, 157.42 and 99.50

Step by Step Solution

1. Step 1: Write the proportion equation
   105.72 : 157.42 = 99.50 : x
2. Step 2: Convert to fraction form
   105.72/157.42 = 99.50/x
3. Step 3: Cross multiply
   105.72x = 157.42 × 99.50
4. Step 4: Simplify right side
   105.72x = 15,663.29
5. Step 5: Solve for x
   x = 15,663.29/105.72
6. Step 6: Final answer
   x = 148.16