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Finding the Fourth Proportional to 694.70, 1,042.10 and 420.20

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Solution

The fourth proportional to 694.70, 1,042.10 and 420.20 is: 630.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    694.70 : 1,042.10 = 420.20 : x
  2. Step 2: Convert to fraction form
    694.70/1,042.10 = 420.20/x
  3. Step 3: Cross multiply
    694.70x = 1,042.10 × 420.20
  4. Step 4: Simplify right side
    694.70x = 437,890.42
  5. Step 5: Solve for x
    x = 437,890.42/694.70
  6. Step 6: Final answer
    x = 630.33

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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.