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Finding the Fourth Proportional to 828.79, 1,243.35 and 315.75

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Solution

The fourth proportional to 828.79, 1,243.35 and 315.75 is: 473.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.79 : 1,243.35 = 315.75 : x
  2. Step 2: Convert to fraction form
    828.79/1,243.35 = 315.75/x
  3. Step 3: Cross multiply
    828.79x = 1,243.35 × 315.75
  4. Step 4: Simplify right side
    828.79x = 392,587.76
  5. Step 5: Solve for x
    x = 392,587.76/828.79
  6. Step 6: Final answer
    x = 473.69

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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.