Finding the Fourth Proportional to 3,948.89, 5,918.86 and 1,315.79

Step by Step Solution

1. Step 1: Write the proportion equation
   3,948.89 : 5,918.86 = 1,315.79 : x
2. Step 2: Convert to fraction form
   3,948.89/5,918.86 = 1,315.79/x
3. Step 3: Cross multiply
   3,948.89x = 5,918.86 × 1,315.79
4. Step 4: Simplify right side
   3,948.89x = 7,787,940.63
5. Step 5: Solve for x
   x = 7,787,940.63/3,948.89
6. Step 6: Final answer
   x = 1,972.18