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Finding the Fourth Proportional to 869.76, 1,304.78 and 431.03

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Solution

The fourth proportional to 869.76, 1,304.78 and 431.03 is: 646.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.76 : 1,304.78 = 431.03 : x
  2. Step 2: Convert to fraction form
    869.76/1,304.78 = 431.03/x
  3. Step 3: Cross multiply
    869.76x = 1,304.78 × 431.03
  4. Step 4: Simplify right side
    869.76x = 562,394.71
  5. Step 5: Solve for x
    x = 562,394.71/869.76
  6. Step 6: Final answer
    x = 646.61

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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.