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Finding the Fourth Proportional to 666.85, 920.25 and 387.25

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Solution

The fourth proportional to 666.85, 920.25 and 387.25 is: 534.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.85 : 920.25 = 387.25 : x
  2. Step 2: Convert to fraction form
    666.85/920.25 = 387.25/x
  3. Step 3: Cross multiply
    666.85x = 920.25 × 387.25
  4. Step 4: Simplify right side
    666.85x = 356,366.81
  5. Step 5: Solve for x
    x = 356,366.81/666.85
  6. Step 6: Final answer
    x = 534.40

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Double scale
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Similar ratio
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1.5x scale

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.