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Finding the Fourth Proportional to 421.33, 631.41 and 215.40

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Solution

The fourth proportional to 421.33, 631.41 and 215.40 is: 322.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.33 : 631.41 = 215.40 : x
  2. Step 2: Convert to fraction form
    421.33/631.41 = 215.40/x
  3. Step 3: Cross multiply
    421.33x = 631.41 × 215.40
  4. Step 4: Simplify right side
    421.33x = 136,005.71
  5. Step 5: Solve for x
    x = 136,005.71/421.33
  6. Step 6: Final answer
    x = 322.80

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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.