Finding the Fourth Proportional to 12,870.66, 17,756.31 and 7,830.84

Step by Step Solution

1. Step 1: Write the proportion equation
   12,870.66 : 17,756.31 = 7,830.84 : x
2. Step 2: Convert to fraction form
   12,870.66/17,756.31 = 7,830.84/x
3. Step 3: Cross multiply
   12,870.66x = 17,756.31 × 7,830.84
4. Step 4: Simplify right side
   12,870.66x = 139,046,822.60
5. Step 5: Solve for x
   x = 139,046,822.60/12,870.66
6. Step 6: Final answer
   x = 10,803.39