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Finding the Fourth Proportional to 420.25, 630.44 and 212.11

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Solution

The fourth proportional to 420.25, 630.44 and 212.11 is: 318.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.25 : 630.44 = 212.11 : x
  2. Step 2: Convert to fraction form
    420.25/630.44 = 212.11/x
  3. Step 3: Cross multiply
    420.25x = 630.44 × 212.11
  4. Step 4: Simplify right side
    420.25x = 133,722.63
  5. Step 5: Solve for x
    x = 133,722.63/420.25
  6. Step 6: Final answer
    x = 318.20

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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.