Finding the Fourth Proportional to 124.86, 172.50 and 100.50

Step by Step Solution

1. Step 1: Write the proportion equation
   124.86 : 172.50 = 100.50 : x
2. Step 2: Convert to fraction form
   124.86/172.50 = 100.50/x
3. Step 3: Cross multiply
   124.86x = 172.50 × 100.50
4. Step 4: Simplify right side
   124.86x = 17,336.25
5. Step 5: Solve for x
   x = 17,336.25/124.86
6. Step 6: Final answer
   x = 138.85