Finding the Fourth Proportional to 21,483.42, 29,646.18 and 12,987.60

Step by Step Solution

1. Step 1: Write the proportion equation
   21,483.42 : 29,646.18 = 12,987.60 : x
2. Step 2: Convert to fraction form
   21,483.42/29,646.18 = 12,987.60/x
3. Step 3: Cross multiply
   21,483.42x = 29,646.18 × 12,987.60
4. Step 4: Simplify right side
   21,483.42x = 385,032,727.37
5. Step 5: Solve for x
   x = 385,032,727.37/21,483.42
6. Step 6: Final answer
   x = 17,922.32