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Finding the Fourth Proportional to 1,005.39, 1,508.28 and 428.25

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Solution

The fourth proportional to 1,005.39, 1,508.28 and 428.25 is: 642.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005.39 : 1,508.28 = 428.25 : x
  2. Step 2: Convert to fraction form
    1,005.39/1,508.28 = 428.25/x
  3. Step 3: Cross multiply
    1,005.39x = 1,508.28 × 428.25
  4. Step 4: Simplify right side
    1,005.39x = 645,920.91
  5. Step 5: Solve for x
    x = 645,920.91/1,005.39
  6. Step 6: Final answer
    x = 642.46

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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.