Finding the Fourth Proportional to 21,978.96, 30,330.80 and 12,547.50

Step by Step Solution

1. Step 1: Write the proportion equation
   21,978.96 : 30,330.80 = 12,547.50 : x
2. Step 2: Convert to fraction form
   21,978.96/30,330.80 = 12,547.50/x
3. Step 3: Cross multiply
   21,978.96x = 30,330.80 × 12,547.50
4. Step 4: Simplify right side
   21,978.96x = 380,575,498.61
5. Step 5: Solve for x
   x = 380,575,498.61/21,978.96
6. Step 6: Final answer
   x = 17,315.45