Finding the Fourth Proportional to 67.49, 100.80 and 57.81

Step by Step Solution

1. Step 1: Write the proportion equation
   67.49 : 100.80 = 57.81 : x
2. Step 2: Convert to fraction form
   67.49/100.80 = 57.81/x
3. Step 3: Cross multiply
   67.49x = 100.80 × 57.81
4. Step 4: Simplify right side
   67.49x = 5,827.25
5. Step 5: Solve for x
   x = 5,827.25/67.49
6. Step 6: Final answer
   x = 86.35