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Finding the Fourth Proportional to 665.52, 998.20 and 421.30

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Solution

The fourth proportional to 665.52, 998.20 and 421.30 is: 631.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.52 : 998.20 = 421.30 : x
  2. Step 2: Convert to fraction form
    665.52/998.20 = 421.30/x
  3. Step 3: Cross multiply
    665.52x = 998.20 × 421.30
  4. Step 4: Simplify right side
    665.52x = 420,541.66
  5. Step 5: Solve for x
    x = 420,541.66/665.52
  6. Step 6: Final answer
    x = 631.90

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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.