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Finding the Fourth Proportional to 415.12, 620.70 and 405.40

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Solution

The fourth proportional to 415.12, 620.70 and 405.40 is: 606.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    415.12 : 620.70 = 405.40 : x
  2. Step 2: Convert to fraction form
    415.12/620.70 = 405.40/x
  3. Step 3: Cross multiply
    415.12x = 620.70 × 405.40
  4. Step 4: Simplify right side
    415.12x = 251,631.78
  5. Step 5: Solve for x
    x = 251,631.78/415.12
  6. Step 6: Final answer
    x = 606.17

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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.