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Finding the Fourth Proportional to 421.29, 631.40 and 215.42

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Solution

The fourth proportional to 421.29, 631.40 and 215.42 is: 322.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.29 : 631.40 = 215.42 : x
  2. Step 2: Convert to fraction form
    421.29/631.40 = 215.42/x
  3. Step 3: Cross multiply
    421.29x = 631.40 × 215.42
  4. Step 4: Simplify right side
    421.29x = 136,011.95
  5. Step 5: Solve for x
    x = 136,011.95/421.29
  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.