Finding the Fourth Proportional to 9,412.78, 12,990.04 and 5,635.21

Step by Step Solution

1. Step 1: Write the proportion equation
   9,412.78 : 12,990.04 = 5,635.21 : x
2. Step 2: Convert to fraction form
   9,412.78/12,990.04 = 5,635.21/x
3. Step 3: Cross multiply
   9,412.78x = 12,990.04 × 5,635.21
4. Step 4: Simplify right side
   9,412.78x = 73,201,603.31
5. Step 5: Solve for x
   x = 73,201,603.31/9,412.78
6. Step 6: Final answer
   x = 7,776.84