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Finding the Fourth Proportional to 680.20, 1,020.30 and 289.78

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Solution

The fourth proportional to 680.20, 1,020.30 and 289.78 is: 434.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.20 : 1,020.30 = 289.78 : x
  2. Step 2: Convert to fraction form
    680.20/1,020.30 = 289.78/x
  3. Step 3: Cross multiply
    680.20x = 1,020.30 × 289.78
  4. Step 4: Simplify right side
    680.20x = 295,658.90
  5. Step 5: Solve for x
    x = 295,658.90/680.20
  6. Step 6: Final answer
    x = 434.67

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.