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Finding the Fourth Proportional to 428.48, 638.30 and 415.57

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Solution

The fourth proportional to 428.48, 638.30 and 415.57 is: 619.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.48 : 638.30 = 415.57 : x
  2. Step 2: Convert to fraction form
    428.48/638.30 = 415.57/x
  3. Step 3: Cross multiply
    428.48x = 638.30 × 415.57
  4. Step 4: Simplify right side
    428.48x = 265,258.33
  5. Step 5: Solve for x
    x = 265,258.33/428.48
  6. Step 6: Final answer
    x = 619.07

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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.