Finding the Fourth Proportional to 101.58, 140.18 and 72.12

Step by Step Solution

1. Step 1: Write the proportion equation
   101.58 : 140.18 = 72.12 : x
2. Step 2: Convert to fraction form
   101.58/140.18 = 72.12/x
3. Step 3: Cross multiply
   101.58x = 140.18 × 72.12
4. Step 4: Simplify right side
   101.58x = 10,109.78
5. Step 5: Solve for x
   x = 10,109.78/101.58
6. Step 6: Final answer
   x = 99.53