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Finding the Fourth Proportional to 420.86, 631.44 and 215.22

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Solution

The fourth proportional to 420.86, 631.44 and 215.22 is: 322.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.86 : 631.44 = 215.22 : x
  2. Step 2: Convert to fraction form
    420.86/631.44 = 215.22/x
  3. Step 3: Cross multiply
    420.86x = 631.44 × 215.22
  4. Step 4: Simplify right side
    420.86x = 135,898.52
  5. Step 5: Solve for x
    x = 135,898.52/420.86
  6. Step 6: Final answer
    x = 322.91

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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.