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Finding the Fourth Proportional to 420.59, 631.28 and 215.31

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Solution

The fourth proportional to 420.59, 631.28 and 215.31 is: 323.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.59 : 631.28 = 215.31 : x
  2. Step 2: Convert to fraction form
    420.59/631.28 = 215.31/x
  3. Step 3: Cross multiply
    420.59x = 631.28 × 215.31
  4. Step 4: Simplify right side
    420.59x = 135,920.90
  5. Step 5: Solve for x
    x = 135,920.90/420.59
  6. Step 6: Final answer
    x = 323.17

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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.