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Finding the Fourth Proportional to 818.78, 1,228.17 and 386.24

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Solution

The fourth proportional to 818.78, 1,228.17 and 386.24 is: 579.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.78 : 1,228.17 = 386.24 : x
  2. Step 2: Convert to fraction form
    818.78/1,228.17 = 386.24/x
  3. Step 3: Cross multiply
    818.78x = 1,228.17 × 386.24
  4. Step 4: Simplify right side
    818.78x = 474,368.38
  5. Step 5: Solve for x
    x = 474,368.38/818.78
  6. Step 6: Final answer
    x = 579.36

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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.