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Finding the Fourth Proportional to 828.72, 1,243.20 and 315.60

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Solution

The fourth proportional to 828.72, 1,243.20 and 315.60 is: 473.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.72 : 1,243.20 = 315.60 : x
  2. Step 2: Convert to fraction form
    828.72/1,243.20 = 315.60/x
  3. Step 3: Cross multiply
    828.72x = 1,243.20 × 315.60
  4. Step 4: Simplify right side
    828.72x = 392,353.92
  5. Step 5: Solve for x
    x = 392,353.92/828.72
  6. Step 6: Final answer
    x = 473.45

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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.