Finding the Fourth Proportional to 38,987.34, 53,805.72 and 21,990.72

Step by Step Solution

1. Step 1: Write the proportion equation
   38,987.34 : 53,805.72 = 21,990.72 : x
2. Step 2: Convert to fraction form
   38,987.34/53,805.72 = 21,990.72/x
3. Step 3: Cross multiply
   38,987.34x = 53,805.72 × 21,990.72
4. Step 4: Simplify right side
   38,987.34x = 1,183,226,522.92
5. Step 5: Solve for x
   x = 1,183,226,522.92/38,987.34
6. Step 6: Final answer
   x = 30,348.99