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Finding the Fourth Proportional to 869.90, 1,306.20 and 664.70

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Solution

The fourth proportional to 869.90, 1,306.20 and 664.70 is: 998.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.90 : 1,306.20 = 664.70 : x
  2. Step 2: Convert to fraction form
    869.90/1,306.20 = 664.70/x
  3. Step 3: Cross multiply
    869.90x = 1,306.20 × 664.70
  4. Step 4: Simplify right side
    869.90x = 868,231.14
  5. Step 5: Solve for x
    x = 868,231.14/869.90
  6. Step 6: Final answer
    x = 998.08

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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.