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Finding the Fourth Proportional to 818.74, 1,228.72 and 386.20

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Solution

The fourth proportional to 818.74, 1,228.72 and 386.20 is: 579.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.74 : 1,228.72 = 386.20 : x
  2. Step 2: Convert to fraction form
    818.74/1,228.72 = 386.20/x
  3. Step 3: Cross multiply
    818.74x = 1,228.72 × 386.20
  4. Step 4: Simplify right side
    818.74x = 474,532.96
  5. Step 5: Solve for x
    x = 474,532.96/818.74
  6. Step 6: Final answer
    x = 579.59

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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.