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Finding the Fourth Proportional to 818.78, 1,228.18 and 331.72

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Solution

The fourth proportional to 818.78, 1,228.18 and 331.72 is: 497.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.78 : 1,228.18 = 331.72 : x
  2. Step 2: Convert to fraction form
    818.78/1,228.18 = 331.72/x
  3. Step 3: Cross multiply
    818.78x = 1,228.18 × 331.72
  4. Step 4: Simplify right side
    818.78x = 407,410.75
  5. Step 5: Solve for x
    x = 407,410.75/818.78
  6. Step 6: Final answer
    x = 497.58

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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.