Finding the Fourth Proportional to 72.55, 100.12 and 56.15

Step by Step Solution

1. Step 1: Write the proportion equation
   72.55 : 100.12 = 56.15 : x
2. Step 2: Convert to fraction form
   72.55/100.12 = 56.15/x
3. Step 3: Cross multiply
   72.55x = 100.12 × 56.15
4. Step 4: Simplify right side
   72.55x = 5,621.10
5. Step 5: Solve for x
   x = 5,621.10/72.55
6. Step 6: Final answer
   x = 77.48