Finding the Fourth Proportional to 1,678.50, 2,515.59 and 1,242.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,678.50 : 2,515.59 = 1,242.18 : x
2. Step 2: Convert to fraction form
   1,678.50/2,515.59 = 1,242.18/x
3. Step 3: Cross multiply
   1,678.50x = 2,515.59 × 1,242.18
4. Step 4: Simplify right side
   1,678.50x = 3,124,815.59
5. Step 5: Solve for x
   x = 3,124,815.59/1,678.50
6. Step 6: Final answer
   x = 1,861.67