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Finding the Fourth Proportional to 1,007.20, 1,509.18 and 421.71

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Solution

The fourth proportional to 1,007.20, 1,509.18 and 421.71 is: 631.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,007.20 : 1,509.18 = 421.71 : x
  2. Step 2: Convert to fraction form
    1,007.20/1,509.18 = 421.71/x
  3. Step 3: Cross multiply
    1,007.20x = 1,509.18 × 421.71
  4. Step 4: Simplify right side
    1,007.20x = 636,436.30
  5. Step 5: Solve for x
    x = 636,436.30/1,007.20
  6. Step 6: Final answer
    x = 631.89

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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.