Finding the Fourth Proportional to 1,200.21, 1,800.76 and 679.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,200.21 : 1,800.76 = 679.88 : x
2. Step 2: Convert to fraction form
   1,200.21/1,800.76 = 679.88/x
3. Step 3: Cross multiply
   1,200.21x = 1,800.76 × 679.88
4. Step 4: Simplify right side
   1,200.21x = 1,224,300.71
5. Step 5: Solve for x
   x = 1,224,300.71/1,200.21
6. Step 6: Final answer
   x = 1,020.07