Finding the Fourth Proportional to 100.07, 138.03 and 72.50

Step by Step Solution

1. Step 1: Write the proportion equation
   100.07 : 138.03 = 72.50 : x
2. Step 2: Convert to fraction form
   100.07/138.03 = 72.50/x
3. Step 3: Cross multiply
   100.07x = 138.03 × 72.50
4. Step 4: Simplify right side
   100.07x = 10,007.18
5. Step 5: Solve for x
   x = 10,007.18/100.07
6. Step 6: Final answer
   x = 100.00