Finding the Fourth Proportional to 30,931.08, 42,719.86 and 20,842.01

Step by Step Solution

1. Step 1: Write the proportion equation
   30,931.08 : 42,719.86 = 20,842.01 : x
2. Step 2: Convert to fraction form
   30,931.08/42,719.86 = 20,842.01/x
3. Step 3: Cross multiply
   30,931.08x = 42,719.86 × 20,842.01
4. Step 4: Simplify right side
   30,931.08x = 890,367,535.72
5. Step 5: Solve for x
   x = 890,367,535.72/30,931.08
6. Step 6: Final answer
   x = 28,785.53