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Finding the Fourth Proportional to 813.84, 1,221.36 and 381.30

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Solution

The fourth proportional to 813.84, 1,221.36 and 381.30 is: 572.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.84 : 1,221.36 = 381.30 : x
  2. Step 2: Convert to fraction form
    813.84/1,221.36 = 381.30/x
  3. Step 3: Cross multiply
    813.84x = 1,221.36 × 381.30
  4. Step 4: Simplify right side
    813.84x = 465,704.57
  5. Step 5: Solve for x
    x = 465,704.57/813.84
  6. Step 6: Final answer
    x = 572.23

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.