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Finding the Fourth Proportional to 427.84, 638.81 and 420.28

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Solution

The fourth proportional to 427.84, 638.81 and 420.28 is: 627.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.84 : 638.81 = 420.28 : x
  2. Step 2: Convert to fraction form
    427.84/638.81 = 420.28/x
  3. Step 3: Cross multiply
    427.84x = 638.81 × 420.28
  4. Step 4: Simplify right side
    427.84x = 268,479.07
  5. Step 5: Solve for x
    x = 268,479.07/427.84
  6. Step 6: Final answer
    x = 627.52

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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.