Finding the Fourth Proportional to 72.99, 100.78 and 54.63

Step by Step Solution

1. Step 1: Write the proportion equation
   72.99 : 100.78 = 54.63 : x
2. Step 2: Convert to fraction form
   72.99/100.78 = 54.63/x
3. Step 3: Cross multiply
   72.99x = 100.78 × 54.63
4. Step 4: Simplify right side
   72.99x = 5,505.47
5. Step 5: Solve for x
   x = 5,505.47/72.99
6. Step 6: Final answer
   x = 75.43