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Finding the Fourth Proportional to 819.30, 1,228.95 and 386.22

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Solution

The fourth proportional to 819.30, 1,228.95 and 386.22 is: 579.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.30 : 1,228.95 = 386.22 : x
  2. Step 2: Convert to fraction form
    819.30/1,228.95 = 386.22/x
  3. Step 3: Cross multiply
    819.30x = 1,228.95 × 386.22
  4. Step 4: Simplify right side
    819.30x = 474,645.07
  5. Step 5: Solve for x
    x = 474,645.07/819.30
  6. Step 6: Final answer
    x = 579.33

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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.