Finding the Fourth Proportional to 31,008.65, 42,742.80 and 28,434.42

Step by Step Solution

1. Step 1: Write the proportion equation
   31,008.65 : 42,742.80 = 28,434.42 : x
2. Step 2: Convert to fraction form
   31,008.65/42,742.80 = 28,434.42/x
3. Step 3: Cross multiply
   31,008.65x = 42,742.80 × 28,434.42
4. Step 4: Simplify right side
   31,008.65x = 1,215,366,727.18
5. Step 5: Solve for x
   x = 1,215,366,727.18/31,008.65
6. Step 6: Final answer
   x = 39,194.45