Finding the Fourth Proportional to 72.65, 100.29 and 57.05

Step by Step Solution

1. Step 1: Write the proportion equation
   72.65 : 100.29 = 57.05 : x
2. Step 2: Convert to fraction form
   72.65/100.29 = 57.05/x
3. Step 3: Cross multiply
   72.65x = 100.29 × 57.05
4. Step 4: Simplify right side
   72.65x = 5,721.88
5. Step 5: Solve for x
   x = 5,721.88/72.65
6. Step 6: Final answer
   x = 78.76