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Finding the Fourth Proportional to 667.10, 920.40 and 405.20

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Solution

The fourth proportional to 667.10, 920.40 and 405.20 is: 559.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    667.10 : 920.40 = 405.20 : x
  2. Step 2: Convert to fraction form
    667.10/920.40 = 405.20/x
  3. Step 3: Cross multiply
    667.10x = 920.40 × 405.20
  4. Step 4: Simplify right side
    667.10x = 372,946.08
  5. Step 5: Solve for x
    x = 372,946.08/667.10
  6. Step 6: Final answer
    x = 559.06

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.