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Finding the Fourth Proportional to 420.20, 630.16 and 203.64

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Solution

The fourth proportional to 420.20, 630.16 and 203.64 is: 305.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.20 : 630.16 = 203.64 : x
  2. Step 2: Convert to fraction form
    420.20/630.16 = 203.64/x
  3. Step 3: Cross multiply
    420.20x = 630.16 × 203.64
  4. Step 4: Simplify right side
    420.20x = 128,325.78
  5. Step 5: Solve for x
    x = 128,325.78/420.20
  6. Step 6: Final answer
    x = 305.39

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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.