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Finding the Fourth Proportional to 420.21, 630.43 and 203.76

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Solution

The fourth proportional to 420.21, 630.43 and 203.76 is: 305.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.21 : 630.43 = 203.76 : x
  2. Step 2: Convert to fraction form
    420.21/630.43 = 203.76/x
  3. Step 3: Cross multiply
    420.21x = 630.43 × 203.76
  4. Step 4: Simplify right side
    420.21x = 128,455.91
  5. Step 5: Solve for x
    x = 128,455.91/420.21
  6. Step 6: Final answer
    x = 305.69

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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.