Finding the Fourth Proportional to 1,120.72, 1,680.76 and 351.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,120.72 : 1,680.76 = 351.12 : x
2. Step 2: Convert to fraction form
   1,120.72/1,680.76 = 351.12/x
3. Step 3: Cross multiply
   1,120.72x = 1,680.76 × 351.12
4. Step 4: Simplify right side
   1,120.72x = 590,148.45
5. Step 5: Solve for x
   x = 590,148.45/1,120.72
6. Step 6: Final answer
   x = 526.58