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Finding the Fourth Proportional to 666.80, 920.40 and 470.40

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Solution

The fourth proportional to 666.80, 920.40 and 470.40 is: 649.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.80 : 920.40 = 470.40 : x
  2. Step 2: Convert to fraction form
    666.80/920.40 = 470.40/x
  3. Step 3: Cross multiply
    666.80x = 920.40 × 470.40
  4. Step 4: Simplify right side
    666.80x = 432,956.16
  5. Step 5: Solve for x
    x = 432,956.16/666.80
  6. Step 6: Final answer
    x = 649.30

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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.