Finding the Fourth Proportional to 72.69, 100.28 and 56.31

Step by Step Solution

1. Step 1: Write the proportion equation
   72.69 : 100.28 = 56.31 : x
2. Step 2: Convert to fraction form
   72.69/100.28 = 56.31/x
3. Step 3: Cross multiply
   72.69x = 100.28 × 56.31
4. Step 4: Simplify right side
   72.69x = 5,646.49
5. Step 5: Solve for x
   x = 5,646.49/72.69
6. Step 6: Final answer
   x = 77.68