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Finding the Fourth Proportional to 421.29, 630.72 and 311.40

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Solution

The fourth proportional to 421.29, 630.72 and 311.40 is: 466.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.29 : 630.72 = 311.40 : x
  2. Step 2: Convert to fraction form
    421.29/630.72 = 311.40/x
  3. Step 3: Cross multiply
    421.29x = 630.72 × 311.40
  4. Step 4: Simplify right side
    421.29x = 196,406.21
  5. Step 5: Solve for x
    x = 196,406.21/421.29
  6. Step 6: Final answer
    x = 466.20

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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.