Finding the Fourth Proportional to 15,870.42, 21,851.32 and 13,475.40

Step by Step Solution

1. Step 1: Write the proportion equation
   15,870.42 : 21,851.32 = 13,475.40 : x
2. Step 2: Convert to fraction form
   15,870.42/21,851.32 = 13,475.40/x
3. Step 3: Cross multiply
   15,870.42x = 21,851.32 × 13,475.40
4. Step 4: Simplify right side
   15,870.42x = 294,455,210.15
5. Step 5: Solve for x
   x = 294,455,210.15/15,870.42
6. Step 6: Final answer
   x = 18,553.71