Finding the Fourth Proportional to 12,907.81, 17,808.51 and 7,870.19

Step by Step Solution

1. Step 1: Write the proportion equation
   12,907.81 : 17,808.51 = 7,870.19 : x
2. Step 2: Convert to fraction form
   12,907.81/17,808.51 = 7,870.19/x
3. Step 3: Cross multiply
   12,907.81x = 17,808.51 × 7,870.19
4. Step 4: Simplify right side
   12,907.81x = 140,156,401.84
5. Step 5: Solve for x
   x = 140,156,401.84/12,907.81
6. Step 6: Final answer
   x = 10,858.27