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Finding the Fourth Proportional to 680.80, 1,021.25 and 218.56

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Solution

The fourth proportional to 680.80, 1,021.25 and 218.56 is: 327.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.80 : 1,021.25 = 218.56 : x
  2. Step 2: Convert to fraction form
    680.80/1,021.25 = 218.56/x
  3. Step 3: Cross multiply
    680.80x = 1,021.25 × 218.56
  4. Step 4: Simplify right side
    680.80x = 223,204.40
  5. Step 5: Solve for x
    x = 223,204.40/680.80
  6. Step 6: Final answer
    x = 327.86

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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.