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Finding the Fourth Proportional to 422.40, 628.80 and 420.48

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Solution

The fourth proportional to 422.40, 628.80 and 420.48 is: 625.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    422.40 : 628.80 = 420.48 : x
  2. Step 2: Convert to fraction form
    422.40/628.80 = 420.48/x
  3. Step 3: Cross multiply
    422.40x = 628.80 × 420.48
  4. Step 4: Simplify right side
    422.40x = 264,397.82
  5. Step 5: Solve for x
    x = 264,397.82/422.40
  6. Step 6: Final answer
    x = 625.94

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.