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Finding the Fourth Proportional to 643.72, 888.18 and 381.69

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Solution

The fourth proportional to 643.72, 888.18 and 381.69 is: 526.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.72 : 888.18 = 381.69 : x
  2. Step 2: Convert to fraction form
    643.72/888.18 = 381.69/x
  3. Step 3: Cross multiply
    643.72x = 888.18 × 381.69
  4. Step 4: Simplify right side
    643.72x = 339,009.42
  5. Step 5: Solve for x
    x = 339,009.42/643.72
  6. Step 6: Final answer
    x = 526.64

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Double scale
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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.