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Finding the Fourth Proportional to 419.76, 628.70 and 257.09

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Solution

The fourth proportional to 419.76, 628.70 and 257.09 is: 385.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.76 : 628.70 = 257.09 : x
  2. Step 2: Convert to fraction form
    419.76/628.70 = 257.09/x
  3. Step 3: Cross multiply
    419.76x = 628.70 × 257.09
  4. Step 4: Simplify right side
    419.76x = 161,628.05
  5. Step 5: Solve for x
    x = 161,628.05/419.76
  6. Step 6: Final answer
    x = 385.05

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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.