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Finding the Fourth Proportional to 659.54, 988.20 and 428.09

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Solution

The fourth proportional to 659.54, 988.20 and 428.09 is: 641.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    659.54 : 988.20 = 428.09 : x
  2. Step 2: Convert to fraction form
    659.54/988.20 = 428.09/x
  3. Step 3: Cross multiply
    659.54x = 988.20 × 428.09
  4. Step 4: Simplify right side
    659.54x = 423,033.60
  5. Step 5: Solve for x
    x = 423,033.60/659.54
  6. Step 6: Final answer
    x = 641.40

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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.