Finding the Fourth Proportional to 102.88, 141.98 and 56.88

Step by Step Solution

1. Step 1: Write the proportion equation
   102.88 : 141.98 = 56.88 : x
2. Step 2: Convert to fraction form
   102.88/141.98 = 56.88/x
3. Step 3: Cross multiply
   102.88x = 141.98 × 56.88
4. Step 4: Simplify right side
   102.88x = 8,075.82
5. Step 5: Solve for x
   x = 8,075.82/102.88
6. Step 6: Final answer
   x = 78.50