Finding the Fourth Proportional to 78.39, 108.09 and 53.50

Step by Step Solution

1. Step 1: Write the proportion equation
   78.39 : 108.09 = 53.50 : x
2. Step 2: Convert to fraction form
   78.39/108.09 = 53.50/x
3. Step 3: Cross multiply
   78.39x = 108.09 × 53.50
4. Step 4: Simplify right side
   78.39x = 5,782.82
5. Step 5: Solve for x
   x = 5,782.82/78.39
6. Step 6: Final answer
   x = 73.77