Finding the Fourth Proportional to 1,217.90, 1,680.72 and 693.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,217.90 : 1,680.72 = 693.92 : x
2. Step 2: Convert to fraction form
   1,217.90/1,680.72 = 693.92/x
3. Step 3: Cross multiply
   1,217.90x = 1,680.72 × 693.92
4. Step 4: Simplify right side
   1,217.90x = 1,166,285.22
5. Step 5: Solve for x
   x = 1,166,285.22/1,217.90
6. Step 6: Final answer
   x = 957.62