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Finding the Fourth Proportional to 420.57, 626.88 and 387.76

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Solution

The fourth proportional to 420.57, 626.88 and 387.76 is: 577.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.57 : 626.88 = 387.76 : x
  2. Step 2: Convert to fraction form
    420.57/626.88 = 387.76/x
  3. Step 3: Cross multiply
    420.57x = 626.88 × 387.76
  4. Step 4: Simplify right side
    420.57x = 243,078.99
  5. Step 5: Solve for x
    x = 243,078.99/420.57
  6. Step 6: Final answer
    x = 577.98

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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.