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Finding the Fourth Proportional to 421.84, 631.29 and 311.90

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Solution

The fourth proportional to 421.84, 631.29 and 311.90 is: 466.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.84 : 631.29 = 311.90 : x
  2. Step 2: Convert to fraction form
    421.84/631.29 = 311.90/x
  3. Step 3: Cross multiply
    421.84x = 631.29 × 311.90
  4. Step 4: Simplify right side
    421.84x = 196,899.35
  5. Step 5: Solve for x
    x = 196,899.35/421.84
  6. Step 6: Final answer
    x = 466.76

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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.