Finding the Fourth Proportional to 77.69, 107.16 and 53.15

Step by Step Solution

1. Step 1: Write the proportion equation
   77.69 : 107.16 = 53.15 : x
2. Step 2: Convert to fraction form
   77.69/107.16 = 53.15/x
3. Step 3: Cross multiply
   77.69x = 107.16 × 53.15
4. Step 4: Simplify right side
   77.69x = 5,695.02
5. Step 5: Solve for x
   x = 5,695.02/77.69
6. Step 6: Final answer
   x = 73.31