Finding the Fourth Proportional to 78.90, 108.89 and 53.02

Step by Step Solution

1. Step 1: Write the proportion equation
   78.90 : 108.89 = 53.02 : x
2. Step 2: Convert to fraction form
   78.90/108.89 = 53.02/x
3. Step 3: Cross multiply
   78.90x = 108.89 × 53.02
4. Step 4: Simplify right side
   78.90x = 5,773.35
5. Step 5: Solve for x
   x = 5,773.35/78.90
6. Step 6: Final answer
   x = 73.17