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Finding the Fourth Proportional to 421.81, 631.63 and 385.09

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Solution

The fourth proportional to 421.81, 631.63 and 385.09 is: 576.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.81 : 631.63 = 385.09 : x
  2. Step 2: Convert to fraction form
    421.81/631.63 = 385.09/x
  3. Step 3: Cross multiply
    421.81x = 631.63 × 385.09
  4. Step 4: Simplify right side
    421.81x = 243,231.85
  5. Step 5: Solve for x
    x = 243,231.85/421.81
  6. Step 6: Final answer
    x = 576.64

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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.