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Finding the Fourth Proportional to 457.38, 682.70 and 420.78

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Solution

The fourth proportional to 457.38, 682.70 and 420.78 is: 628.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    457.38 : 682.70 = 420.78 : x
  2. Step 2: Convert to fraction form
    457.38/682.70 = 420.78/x
  3. Step 3: Cross multiply
    457.38x = 682.70 × 420.78
  4. Step 4: Simplify right side
    457.38x = 287,266.51
  5. Step 5: Solve for x
    x = 287,266.51/457.38
  6. Step 6: Final answer
    x = 628.07

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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.