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Finding the Fourth Proportional to 420.96, 630.99 and 215.31

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Solution

The fourth proportional to 420.96, 630.99 and 215.31 is: 322.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.96 : 630.99 = 215.31 : x
  2. Step 2: Convert to fraction form
    420.96/630.99 = 215.31/x
  3. Step 3: Cross multiply
    420.96x = 630.99 × 215.31
  4. Step 4: Simplify right side
    420.96x = 135,858.46
  5. Step 5: Solve for x
    x = 135,858.46/420.96
  6. Step 6: Final answer
    x = 322.73

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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.