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Finding the Fourth Proportional to 665.70, 998.60 and 421.89

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Solution

The fourth proportional to 665.70, 998.60 and 421.89 is: 632.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.70 : 998.60 = 421.89 : x
  2. Step 2: Convert to fraction form
    665.70/998.60 = 421.89/x
  3. Step 3: Cross multiply
    665.70x = 998.60 × 421.89
  4. Step 4: Simplify right side
    665.70x = 421,297.24
  5. Step 5: Solve for x
    x = 421,297.24/665.70
  6. Step 6: Final answer
    x = 632.86

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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.