Finding the Fourth Proportional to 28,141.68, 42,215.64 and 12,557.28

Step by Step Solution

1. Step 1: Write the proportion equation
   28,141.68 : 42,215.64 = 12,557.28 : x
2. Step 2: Convert to fraction form
   28,141.68/42,215.64 = 12,557.28/x
3. Step 3: Cross multiply
   28,141.68x = 42,215.64 × 12,557.28
4. Step 4: Simplify right side
   28,141.68x = 530,113,611.86
5. Step 5: Solve for x
   x = 530,113,611.86/28,141.68
6. Step 6: Final answer
   x = 18,837.31