Finding the Fourth Proportional to 1,680.71, 2,516.78 and 1,406.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,680.71 : 2,516.78 = 1,406.12 : x
2. Step 2: Convert to fraction form
   1,680.71/2,516.78 = 1,406.12/x
3. Step 3: Cross multiply
   1,680.71x = 2,516.78 × 1,406.12
4. Step 4: Simplify right side
   1,680.71x = 3,538,875.08
5. Step 5: Solve for x
   x = 3,538,875.08/1,680.71
6. Step 6: Final answer
   x = 2,105.59