Finding the Fourth Proportional to 1,213.70, 1,674.72 and 689.63

Step by Step Solution

1. Step 1: Write the proportion equation
   1,213.70 : 1,674.72 = 689.63 : x
2. Step 2: Convert to fraction form
   1,213.70/1,674.72 = 689.63/x
3. Step 3: Cross multiply
   1,213.70x = 1,674.72 × 689.63
4. Step 4: Simplify right side
   1,213.70x = 1,154,928.78
5. Step 5: Solve for x
   x = 1,154,928.78/1,213.70
6. Step 6: Final answer
   x = 951.58