Finding the Fourth Proportional to 42.80, 59.10 and 28.05

Step by Step Solution

1. Step 1: Write the proportion equation
   42.80 : 59.10 = 28.05 : x
2. Step 2: Convert to fraction form
   42.80/59.10 = 28.05/x
3. Step 3: Cross multiply
   42.80x = 59.10 × 28.05
4. Step 4: Simplify right side
   42.80x = 1,657.43
5. Step 5: Solve for x
   x = 1,657.43/42.80
6. Step 6: Final answer
   x = 38.73