Finding the Fourth Proportional to 31.10, 42.86 and 27.99

Step by Step Solution

1. Step 1: Write the proportion equation
   31.10 : 42.86 = 27.99 : x
2. Step 2: Convert to fraction form
   31.10/42.86 = 27.99/x
3. Step 3: Cross multiply
   31.10x = 42.86 × 27.99
4. Step 4: Simplify right side
   31.10x = 1,199.72
5. Step 5: Solve for x
   x = 1,199.72/31.10
6. Step 6: Final answer
   x = 38.58