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Finding the Fourth Proportional to 643.42, 887.92 and 381.45

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Solution

The fourth proportional to 643.42, 887.92 and 381.45 is: 526.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.42 : 887.92 = 381.45 : x
  2. Step 2: Convert to fraction form
    643.42/887.92 = 381.45/x
  3. Step 3: Cross multiply
    643.42x = 887.92 × 381.45
  4. Step 4: Simplify right side
    643.42x = 338,696.13
  5. Step 5: Solve for x
    x = 338,696.13/643.42
  6. Step 6: Final answer
    x = 526.40

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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.