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Finding the Fourth Proportional to 420.68, 631.31 and 215.38

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Solution

The fourth proportional to 420.68, 631.31 and 215.38 is: 323.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.68 : 631.31 = 215.38 : x
  2. Step 2: Convert to fraction form
    420.68/631.31 = 215.38/x
  3. Step 3: Cross multiply
    420.68x = 631.31 × 215.38
  4. Step 4: Simplify right side
    420.68x = 135,967.71
  5. Step 5: Solve for x
    x = 135,967.71/420.68
  6. Step 6: Final answer
    x = 323.21

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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.