Finding the Fourth Proportional to 20,978.42, 31,460.60 and 7,124.18

Step by Step Solution

1. Step 1: Write the proportion equation
   20,978.42 : 31,460.60 = 7,124.18 : x
2. Step 2: Convert to fraction form
   20,978.42/31,460.60 = 7,124.18/x
3. Step 3: Cross multiply
   20,978.42x = 31,460.60 × 7,124.18
4. Step 4: Simplify right side
   20,978.42x = 224,130,977.31
5. Step 5: Solve for x
   x = 224,130,977.31/20,978.42
6. Step 6: Final answer
   x = 10,683.88