Finding the Fourth Proportional to 21,012.58, 28,988.17 and 15,042.07

Step by Step Solution

1. Step 1: Write the proportion equation
   21,012.58 : 28,988.17 = 15,042.07 : x
2. Step 2: Convert to fraction form
   21,012.58/28,988.17 = 15,042.07/x
3. Step 3: Cross multiply
   21,012.58x = 28,988.17 × 15,042.07
4. Step 4: Simplify right side
   21,012.58x = 436,042,082.31
5. Step 5: Solve for x
   x = 436,042,082.31/21,012.58
6. Step 6: Final answer
   x = 20,751.48