Finding the Fourth Proportional to 78.11, 107.72 and 53.50

Step by Step Solution

1. Step 1: Write the proportion equation
   78.11 : 107.72 = 53.50 : x
2. Step 2: Convert to fraction form
   78.11/107.72 = 53.50/x
3. Step 3: Cross multiply
   78.11x = 107.72 × 53.50
4. Step 4: Simplify right side
   78.11x = 5,762.88
5. Step 5: Solve for x
   x = 5,762.88/78.11
6. Step 6: Final answer
   x = 73.78