Finding the Fourth Proportional to 72.61, 100.15 and 51.91

Step by Step Solution

1. Step 1: Write the proportion equation
   72.61 : 100.15 = 51.91 : x
2. Step 2: Convert to fraction form
   72.61/100.15 = 51.91/x
3. Step 3: Cross multiply
   72.61x = 100.15 × 51.91
4. Step 4: Simplify right side
   72.61x = 5,198.79
5. Step 5: Solve for x
   x = 5,198.79/72.61
6. Step 6: Final answer
   x = 71.60