Finding the Fourth Proportional to 19,158.59, 28,723.56 and 13,218.53

Step by Step Solution

1. Step 1: Write the proportion equation
   19,158.59 : 28,723.56 = 13,218.53 : x
2. Step 2: Convert to fraction form
   19,158.59/28,723.56 = 13,218.53/x
3. Step 3: Cross multiply
   19,158.59x = 28,723.56 × 13,218.53
4. Step 4: Simplify right side
   19,158.59x = 379,683,095.95
5. Step 5: Solve for x
   x = 379,683,095.95/19,158.59
6. Step 6: Final answer
   x = 19,817.91