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Finding the Fourth Proportional to 643.60, 887.72 and 381.40

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Solution

The fourth proportional to 643.60, 887.72 and 381.40 is: 526.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.60 : 887.72 = 381.40 : x
  2. Step 2: Convert to fraction form
    643.60/887.72 = 381.40/x
  3. Step 3: Cross multiply
    643.60x = 887.72 × 381.40
  4. Step 4: Simplify right side
    643.60x = 338,576.41
  5. Step 5: Solve for x
    x = 338,576.41/643.60
  6. Step 6: Final answer
    x = 526.07

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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.