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Finding the Fourth Proportional to 420.71, 631.25 and 215.17

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Solution

The fourth proportional to 420.71, 631.25 and 215.17 is: 322.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.71 : 631.25 = 215.17 : x
  2. Step 2: Convert to fraction form
    420.71/631.25 = 215.17/x
  3. Step 3: Cross multiply
    420.71x = 631.25 × 215.17
  4. Step 4: Simplify right side
    420.71x = 135,826.06
  5. Step 5: Solve for x
    x = 135,826.06/420.71
  6. Step 6: Final answer
    x = 322.85

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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.