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Finding the Fourth Proportional to 680.76, 1,021.21 and 218.42

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Solution

The fourth proportional to 680.76, 1,021.21 and 218.42 is: 327.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.76 : 1,021.21 = 218.42 : x
  2. Step 2: Convert to fraction form
    680.76/1,021.21 = 218.42/x
  3. Step 3: Cross multiply
    680.76x = 1,021.21 × 218.42
  4. Step 4: Simplify right side
    680.76x = 223,052.69
  5. Step 5: Solve for x
    x = 223,052.69/680.76
  6. Step 6: Final answer
    x = 327.65

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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.