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Finding the Fourth Proportional to 643.71, 887.99 and 381.81

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Solution

The fourth proportional to 643.71, 887.99 and 381.81 is: 526.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.71 : 887.99 = 381.81 : x
  2. Step 2: Convert to fraction form
    643.71/887.99 = 381.81/x
  3. Step 3: Cross multiply
    643.71x = 887.99 × 381.81
  4. Step 4: Simplify right side
    643.71x = 339,041.55
  5. Step 5: Solve for x
    x = 339,041.55/643.71
  6. Step 6: Final answer
    x = 526.70

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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.