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Finding the Fourth Proportional to 680.70, 1,020.80 and 218.60

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Solution

The fourth proportional to 680.70, 1,020.80 and 218.60 is: 327.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.70 : 1,020.80 = 218.60 : x
  2. Step 2: Convert to fraction form
    680.70/1,020.80 = 218.60/x
  3. Step 3: Cross multiply
    680.70x = 1,020.80 × 218.60
  4. Step 4: Simplify right side
    680.70x = 223,146.15
  5. Step 5: Solve for x
    x = 223,146.15/680.70
  6. Step 6: Final answer
    x = 327.82

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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.