Finding the Fourth Proportional to 21,853.20, 30,158.34 and 12,900.72

Step by Step Solution

1. Step 1: Write the proportion equation
   21,853.20 : 30,158.34 = 12,900.72 : x
2. Step 2: Convert to fraction form
   21,853.20/30,158.34 = 12,900.72/x
3. Step 3: Cross multiply
   21,853.20x = 30,158.34 × 12,900.72
4. Step 4: Simplify right side
   21,853.20x = 389,064,300.00
5. Step 5: Solve for x
   x = 389,064,300.00/21,853.20
6. Step 6: Final answer
   x = 17,803.54