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Finding the Fourth Proportional to 415.40, 622.49 and 386.64

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Solution

The fourth proportional to 415.40, 622.49 and 386.64 is: 579.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    415.40 : 622.49 = 386.64 : x
  2. Step 2: Convert to fraction form
    415.40/622.49 = 386.64/x
  3. Step 3: Cross multiply
    415.40x = 622.49 × 386.64
  4. Step 4: Simplify right side
    415.40x = 240,677.60
  5. Step 5: Solve for x
    x = 240,677.60/415.40
  6. Step 6: Final answer
    x = 579.39

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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.