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Finding the Fourth Proportional to 421.11, 631.98 and 215.85

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Solution

The fourth proportional to 421.11, 631.98 and 215.85 is: 323.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.11 : 631.98 = 215.85 : x
  2. Step 2: Convert to fraction form
    421.11/631.98 = 215.85/x
  3. Step 3: Cross multiply
    421.11x = 631.98 × 215.85
  4. Step 4: Simplify right side
    421.11x = 136,412.88
  5. Step 5: Solve for x
    x = 136,412.88/421.11
  6. Step 6: Final answer
    x = 323.94

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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.