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Finding the Fourth Proportional to 820.05, 1,228.78 and 386.29

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Solution

The fourth proportional to 820.05, 1,228.78 and 386.29 is: 578.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.05 : 1,228.78 = 386.29 : x
  2. Step 2: Convert to fraction form
    820.05/1,228.78 = 386.29/x
  3. Step 3: Cross multiply
    820.05x = 1,228.78 × 386.29
  4. Step 4: Simplify right side
    820.05x = 474,665.43
  5. Step 5: Solve for x
    x = 474,665.43/820.05
  6. Step 6: Final answer
    x = 578.82

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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.