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Finding the Fourth Proportional to 815.45, 1,221.63 and 404.10

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Solution

The fourth proportional to 815.45, 1,221.63 and 404.10 is: 605.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.45 : 1,221.63 = 404.10 : x
  2. Step 2: Convert to fraction form
    815.45/1,221.63 = 404.10/x
  3. Step 3: Cross multiply
    815.45x = 1,221.63 × 404.10
  4. Step 4: Simplify right side
    815.45x = 493,660.68
  5. Step 5: Solve for x
    x = 493,660.68/815.45
  6. Step 6: Final answer
    x = 605.39

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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.